8x12 Insulated Chicken Coop Plans for 14-18 Hens (Free PDF)

Four 4x4 posts cut to 98-3/4" carry the structure from grade to the top plate. Setting the floor 12" up keeps the frame out of ground moisture and hands the flock the shaded space underneath.

The base ring ties the four posts into a rigid square at grade. Use the 4-inch screws here — this joint carries the racking load for the life of the coop.

Joists sit 12" above grade on 16" centres, running the short direction across 90" in 2x6, with the rim doubled on all four sides. At 90" the 2x6 joists span well inside the 8 ft 4 in that AWC DCA6 Table 2 allows at 16-inch centres, so no intermediate girder is needed. Crown every joist up before you fasten it. Where the datum is. Every height in this set is measured from the TOP OF THE PIER BLOCK — the surface the posts actually stand on, not the soil. Set the blocks first, level them to each other with a string line, and treat that plane as zero. If the blocks sit 4in proud of the dirt the finished coop is 4in taller than the numbers here, which is fine; measuring one post from the block and the next from the ground is not. Fixing the floor frame to the posts. This is the joint everything above stands on and it is the one most plans leave to guesswork. Build the rim rectangle first, square it to the diagonals, then drop it over the four posts so the rim sits ON the base ring and CLOSES the outside face of each post. Fasten each corner with two 4in structural screws driven through the rim into the post, one 1-1/2in down from the top of the rim and one 1-1/2in up from the bottom, offset from each other so they are not in the same grain line. Eight screws in total, four corners. Predrill — a 4in screw close to the end of a 2x6 will split it otherwise.

Deck the floor in 3/4" plywood, notched 3-1/2" square at each corner so it drops cleanly around the posts. Fasten with 1-1/2 inch screws every 8 inches on the joists.

Every wall is framed FLAT ON THE DECK and then stood up. That is the whole trick: you are working on a level surface, gravity holds the parts where you put them, and you can push the frame square before a single screw goes in. Studs run 16" on centre so 4-foot sheet goods break on a stud. Build order matters. Front wall, back wall, then the two end walls. The long walls go up first and get braced to the deck; the end walls then drop between them and lock the box square. If you stand a short wall first it has nothing to brace against. Every wall gets three plates: a bottom plate, a top plate, and a cap plate over the top. The cap plate is not a second top plate for strength — it is there to LAP the corner. Hold the long walls' cap plate back 1-1/2" at BOTH ends, and run the end walls' cap 1-1/2" long at BOTH ends. On this coop that is a 134" cap on a 137" long wall and a 92" cap on an 89" end wall. The end-wall caps then run over the long-wall caps at all four corners and tie the walls into one ring. A butt joint at every corner is a box that racks. Cut the bottom plate CONTINUOUS through every door opening. Frame it, stand it, brace it, and only then saw the plate out of the doorway with a handsaw. It is what keeps the wall square while you move it.

The low side. It carries the door and most of the glazing. Plate length 137". Openings: window 18" x 23", walk-in door 34" x 74", window 18" x 23". 39 pieces in this wall. Every dimension on the drawing runs from the LEFT end of the plate to a stud CENTRE. Mark the whole plate out before you cut anything — lay the bottom and top plate side by side, square across both at once, and you cannot get the two out of step.

The HIGH side — its studs are longer than the front wall's by the full rise of the roof. The nest bank hangs outside it and the vent strip runs along the top, so keep the top bay clear. Plate length 137". Openings: nest bank opening 74-1/2" x 13". 27 pieces in this wall. Every dimension on the drawing runs from the LEFT end of the plate to a stud CENTRE. Mark the whole plate out before you cut anything — lay the bottom and top plate side by side, square across both at once, and you cannot get the two out of step.

The run attaches to this wall and the pop door passes through it. Seen from outside, the roof runs DOWNHILL left to right. Plate length 89". Openings: pop door 16" x 18". 24 pieces in this wall. Every dimension on the drawing runs from the LEFT end of the plate to a stud CENTRE. Mark the whole plate out before you cut anything — lay the bottom and top plate side by side, square across both at once, and you cannot get the two out of step.

Outside door into the feed room, plus a window. This wall MIRRORS the left end: seen from outside, the roof runs UPHILL left to right. Plate length 89". Openings: feed-room door 30" x 74", window 18" x 23". 33 pieces in this wall. Every dimension on the drawing runs from the LEFT end of the plate to a stud CENTRE. Mark the whole plate out before you cut anything — lay the bottom and top plate side by side, square across both at once, and you cannot get the two out of step.

A single-slope shed roof at 3:12 — 24" of fall across the 96" width, which is the minimum pitch exposed-fastener corrugated metal will shed reliably. There is no ridge and no opposing rafter pair, so there is no outward thrust and no rafter tie is required — the load lands straight down on the two side walls. That is the quiet advantage of a shed roof over a gable, and it is why this is the simplest roof in our line to frame. Why the rafter is 2x6 and not something shallower. It spans the full 96" width in one piece with nothing under the middle of it, and at 24" centres that is what the span table allows: 2021 IRC Table R802.4.1(4), Spruce-Pine-Fir No.2, 30 psf ground snow, no ceiling attached, 10 psf dead load, gives 117" for a 2x6 — and 117" for a 2x6, which is why a 2x6 is not on this list unless the building is narrower. Span is measured on the HORIZONTAL, so the slope costs you nothing here; the width does. Deeper is not optional and shallower is not a saving, it is a sag.

3/4" plywood over the rafters, then corrugated metal sheets. Metal over shingles because it sheds snow, lasts decades and never needs a tear-off. Lap the sheets one full corrugation.

Lap siding in 9-foot courses, starting from a level chalk line at the bottom and working up. Each course laps the one below by 1 inch. Leave the window and door openings proud and trim after. TWO CONTINUOUS SLOTS GET LEFT IN THIS SKIN, NOT ONE, AND BOTH ARE 5-1/2" HIGH. One along the top of the back wall and one along the top of the front wall, in the top stud bay of each, tight under the underside of the top plate. Snap a second chalk line 5-1/2" below that plate on both walls, die the course on it, and start again above it. These are the permanent ventilation of this coop — 5-1/2" x 134" on the back wall, the same on the front either side of the door — and unlike every other design in this line they are SLOTS rather than an open top of wall, because the insulated ceiling now lands on the cap plate above them. Hardware cloth in step 12, casing and drip cap in step 13d. Treat each slot as a window with no glass. Head casing, sloped sill, drip cap over the head tucked under the course above. A slot cut in lap siding and left raw runs water down the inside of the wall you just insulated. They are never glazed, never blocked and never closed for winter. A coop sided tight all round is a sealed box, and a sealed box in January is wet, then ammoniated, then a respiratory problem — and insulating that box does not fix it, it hides it for a month.

Every opening you framed in step 5 now gets something to close it. Cut each slab a quarter inch smaller than its rough opening on all four sides — 3/4in plywood swells in the wet and a door cut to the exact opening size will bind by November. Then close that gap with a stop. A quarter inch is the clearance the door needs and it is also, exactly, the gap this plan tells you a least weasel fits through. Run a 1x2 stop around the inside of every door opening so the slab closes against it and the gap is blocked, not open. On the pop door, staple a strip of hardware cloth behind the stop as well. Walk-in door on the front wall (low eave): slab 33-1/2" x 73-1/2" in a 34" x 74" opening — a 1/4in gap all round. 3 hinges, out, hinged on the left as you face it from outside. Pop door on the left end wall (run end): slab 15-1/2" x 17-1/2" in a 16" x 18" opening — a 1/4in gap all round. 2 hinges, out, hinged on the left as you face it from outside. Feed-room door on the right end wall (feed room): slab 29-1/2" x 73-1/2" in a 30" x 74" opening — a 1/4in gap all round. 3 hinges, out, hinged on the left as you face it from outside. Every plywood door over 30in tall gets a Z-brace on the back: a rail top and bottom and one diagonal running from the bottom hinge corner up to the top latch corner. That diagonal is in compression and it is the only thing stopping the door sagging into a parallelogram. Run it the wrong way and it does nothing. Hinge side and swing. All doors here swing OUT, hinged on the left as you face them from outside. Out, because a door that opens inward sweeps the bedding and gets blocked by it; left, so every latch on the coop is in the same place and you are not hunting for it in the dark with an armful of feed.

An exterior nest bank 74-1/2" long and 17 inches deep, hung off the side wall with a hinged lid. 5 compartments — one per three to four hens. Collecting eggs from outside means you never disturb a sitting bird.

The pop-door slab was already cut in step 8b to fit the opening you framed in step 5c — do not cut another one. This step hangs it and builds the ramp. Measure the ramp drop on site. It runs from the pop-door sill, 22-1/4" above grade, down to the FINISHED run surface — which is the sand or drain rock you placed in step 11, not bare ground. On a level site that is about 43-1/16" of ramp at a comfortable angle, but cut it to what you measure, not to what is printed here.

The 8 ft x 16 ft screened run frames off the coop wall, 96" tall. 5 posts a side on roughly 4-foot centres, with a top rail and a mid rail so the hardware cloth has something to fasten to at every course. The mid rail goes at 32 inches, not higher — the cloth comes off a 36-inch roll, so a course run up from the ground reaches 36 inches and has to land ON a rail with a lap to spare. Set the run posts the same way you set the coop posts in step 1 — on the same pier blocks, at the same height, checked with the same string line. A run on a different footing system than the coop it hangs off will move against it and open a gap at the joint, which is exactly where a predator starts. Fixing the run to the coop: the two run rails that meet the coop are lag-bolted into the corner posts of the run-end wall, not screwed into siding. Two 3/8in x 4in lag bolts per rail, drilled with a 1/4in pilot, one 3in above the rail's bottom edge and one 3in below its top. Siding is a skin; it holds nothing. The run door is 33" wide — two 2x4 stiles plus 26" rails between them. Hang it in the end bay furthest from the coop so you are not squeezing past the ramp with a bucket. Purlins across the top at every post. A quarter-inch mesh roof spanning eight feet unsupported sags into a hammock and a raccoon can bear it down far enough to get a leg through. The purlins are what the roof mesh fastens to. Get the water out before you put the birds in. A run that ponds turns into mud, mud turns into the coccidiosis and bumblefoot problems that cost people their flock, and no amount of hardware cloth fixes it. Three things, in order of how much they matter: grade the run to fall away from the coop — an inch of drop for every eight feet is enough and it costs you nothing but a rake; keep the run surface above the surrounding grade, not level with it, so it sheds instead of collects; and top it with 3 to 4 inches of coarse sand or 3/8in drain rock, not topsoil and not straw. Coarse sand drains, dries fast and can be raked clean like a litter box. Do this before the apron goes in — you cannot regrade under a buried mesh skirt.

The step that decides whether you still have a flock in two years. Quarter-inch hardware cloth over every opening, screwed through fender washers rather than only stapled. Quarter-inch, not half-inch. A least weasel squeezes through a half-inch opening; quarter-inch mesh stops it. That is the whole reason for the spec (Univ. of Kentucky Extension ID-245), and half-inch mesh — while genuinely raccoon-proof — does not stop weasels, mink or snakes. Chicken wire stops nothing: a raccoon reaches straight through the hexagonal gaps. Bury a 12-inch apron down and out around the whole run perimeter, turned outward at the bottom into an L. Sources for both numbers: Univ. of Kentucky Cooperative Extension ID-245 and Virginia Cooperative Extension 2902-1092. The windows get cloth too. An open 18 x 23 window is a hole a raccoon walks through, and it is the ventilation you rely on in summer, so it has to stay open at night. Staple a panel of cloth to the INSIDE of every window opening before the unit goes in — behind the glazing, not over it, so the window still shuts on a clean frame. Same for the continuous vent strip along the top of the back wall and the nest-bank opening.

Everything in this chapter is about air, not about warmth. A hen puts roughly 0.45 lb of water into this building every day and her manure is about 70% water; 18 of them is about 8 lb — call it 1.0 gallons a day — and not one gram of it is removed by insulation. Univ. of Kentucky's poultry manual puts it in one line: *moisture removal is the primary design consideration for cold weather ventilation.* Insulation changes how warm the coop is. Only the vent changes how wet it is. This is the standard way an insulated backyard coop goes wrong, and it was written down by Univ. of Georgia Extension in 2003: *in efforts to keep their birds warm, some people have constructed backyard housing that is insulated and fairly air tight. This means that the houses have fewer leaks so less fresh air comes in and less air laden with ammonia and moisture leaks out.* Wet litter is not just unpleasant either — USDA-ARS measured litter at 30% moisture releasing 1.8 times the ammonia of litter at 20%. SO THIS COOP HAS TWO SEPARATE AIR PATHS AND YOU MUST NOT CONFUSE THEM. 1. The birds' air — the two 5-1/2" slots at the top of the back and front walls. 877 square inches of NET free area between them, 49 sq in a bird. Permanently open. Never closed, in any weather, at any temperature. 2. The plywood's air — a 2" channel over the roof insulation, in at the low eave and out at the high eave, 445 sq in net. It serves the roof deck, not the flock. Its square inches are not bird ventilation and must never be added to the figure above. Insulating between the rafters moves the wettest cold surface in the building to the underside of that plywood, and this channel is the only thing that dries it. Two detail sheets at the front of this chapter draw all of it: the wall layer by layer with the vent slot through it, and the roof cavity at both eaves at a scale where two inches of air is visible. Work from those, not from this page. Nothing in this chapter is a good idea on its own. Batts without the channel are worse than no batts. Batts without the liner get eaten. Read all five steps before you buy anything.

The two layers nobody expects to buy, and neither is optional once there is a batt in the wall. Every other coop in this line hangs lap siding straight on the studs. That is allowed — IRC R703.2 exempts an accessory building whose siding is *attached directly to studs* from needing a water-resistive barrier — and it is perfectly fine over an EMPTY stud bay. Fill that bay with fiberglass and the outside face of the batt is now the back of lap siding, which leaks air by design. Wind blows through the fiberglass and the number on the bag is not in your wall. So the walls get sheathed: 11 sheets of 7/16 OSB over the studs, seams on framing, 8d nails 6in on the edges and 12in in the field. And that sheathing costs you the exemption. With OSB on, the siding is no longer attached directly to studs, so R703.2 applies and house wrap goes on: 1 roll, shingle-lapped upward, every horizontal seam taped, cut-and-taped around every opening. The Modern coop in this line pays exactly the same forfeit for exactly the same reason — its siding is furred off the studs. LEAVE BOTH SLOTS OPEN. Sheathing and wrap stop at the top-bay slots on the back and front walls the same way the siding does. Sheathing a wall is the easiest possible way to seal a vent, because the panel is 4 ft wide and the slot is 5-1/2" — one sheet in the wrong place closes a third of it and nothing about the wall looks wrong afterwards.

R-13 kraft-faced batts, 3-1/2" thick, 15in wide for 16in centres — 260 sq ft. Friction-fit, do not compress, and split the batt around every wire and pipe rather than crushing it behind one. A 3-1/2in batt is sold as R-13 and also as R-15 in high density; either fits, and the plan is not going to pretend there is one right answer. WHAT THAT NUMBER IS AND IS NOT. R-13 is a label on a bag — Johns Manville's 15 x 93in kraft batt at 3.50in, Owens Corning's EcoTouch, both published. It is not what this wall performs at, and this plan does not print a figure for what this wall performs at, because we have not measured one. The studs bridge straight through the insulation every 16 inches. Oak Ridge National Laboratory measured a 2x4 wall at 16in centres with R-11 batts, plywood outside and gypsum inside: R-13.6 at the centre of the cavity, R-9.6 whole-wall — 70% of it. Their wall is not this wall and their batt is not this batt, which is exactly why we quote their number as theirs and give you none of our own. The only R-value guidance any poultry extension source publishes is Univ. of Kentucky's: good insulating materials are above R-10. A 3-1/2in batt clears that. THE FACING IS THE VAPOR RETARDER AND IT FACES INTO THE COOP. Kraft-faced fiberglass batt is the code's own named example of a Class II vapor retarder (IRC Table R702.7(1)), and Univ. of Kentucky's insulation article puts it on *the side of the material that faces into the poultry house*. Staple the flanges to the face of the studs, paper toward you. Do not then add polyethylene as well. Two retarders on the warm side of one wall traps water between them and there is no way for it to leave. 12 sheets of 1/2in plywood line the inside — and the liner is part of the insulation, not a finish. Univ. of Kentucky, on insulating a poultry house: *your birds should not be exposed to or have access to the insulation or vapor barrier*, and those materials *are attractive to rodents and insects as nesting materials or food sources*. A hen will strip an exposed batt in a week and a rat will move into it. Fasten with 1-1/2in screws at 8in, seams on studs. Every opening gets a return. The liner stops at each rough opening and leaves 3-15/16" of cut batt facing the room. Line all four sides of every one — both vent slots included, and the slot returns are the ones most likely to be forgotten because there is no window in them to make the gap obvious.

This is the step the whole design exists for. Read the arithmetic before you lift a batt. A 2x6 rafter gives you 5-1/2" of bay. Take 3-1/2" of batt and 2" of it is left over, and that 2" is not spare — it is the channel. IRC R806.3 requires *not less than a 1" space between the insulation and the roof sheathing and at the location of the vent*. Building Science Corporation's attic-ventilation digest says the code minimum is not enough and recommends *a minimum 2" clear airspace* in a vented cathedral assembly, because — their words — typical installation tolerances *do not result in an airspace of at least 1 inch and rarely is it clear*. So the target here is 2", twice code, and the geometry happens to hand it to you for free. DO NOT UPGRADE THE BATT. THE 5-1/2" BATT IS THE FAILURE, NOT THE IMPROVEMENT. A 5-1/2in batt fills the bay, the channel goes to zero, and the underside of your roof deck has no way to dry — which is the one condition this chapter is written to prevent. It does not even buy what the bag says: Johns Manville's own load-bearing note is that R-19 in a 5-1/2in cavity *is compressed in this application giving R-17 to R-18*. You would trade a working roof for one point of R. R-13 at 3-1/2", 23in wide for 24in centres, 105 sq ft. Nothing thicker, ever. THE BAFFLES. 12 panels of 1/4in ply, 22-1/2" x 24", one at each end of every rafter bay, on 1x2 cleats nailed to the rafter sides so the baffle's top face sits 2" below the sheathing. Away from the eaves the batt's own thickness holds the channel; at the eaves nothing does, which is where R806.3's words *at the location of the vent* come from. The baffle's 1/4in comes out of the BATT, not out of the air: the batt is nipped to 3-1/4" over those 24", a 7% squeeze, and the channel stays a full 2". That is the right way round to spend it. THE CEILING. 96" sq ft of 1/2in plywood screwed to the underside of the rafters, off the liner count in 13b, and every edge and every seam caulked. This is not tidiness. The ceiling is the air barrier that keeps coop air out of the rafter bays — Building Science Corporation: *an air barrier at the ceiling line should be present to isolate the attic space*. An unsealed ceiling lets the birds' wet air straight into the insulation, and then the channel above it is drying a problem you posted up through the ceiling. Batts go in from below, kraft paper DOWN toward the birds, stapled to the rafter faces. Each bay is 98-15/16" of sloped run.

Rafter blocking comes OUT at both eaves — all 12 bay ends — and hardware cloth goes over each one. On the parent design the blocking is omitted at the high eave only and it is part of the birds' vent. Here the ceiling liner has separated the two, so this is a different vent doing a different job: cold air in at the low eave, up the 2" channel, warm damp air out at the high eave, and nothing about it reaches the flock. The numbers. Six bays each end at 22-1/2" x 2" is 270 sq in an eave; 1/4in cloth is about 82% hole, so 445 sq in of net free area. IRC R806.2 asks for 1/150 of the vented space, which on this 96" sq ft ceiling is 92 sq in. This roof is vented 4.8 times over, so the plan never has to lean on the 1/300 exception or argue about its conditions. 1/4in cloth, and do not upgrade it for airflow. IRC R806.1 caps vent openings at 1/4in and this line already buys 1/4in for the weasel (Univ. of Kentucky ID-245). One cloth is simultaneously the coarsest the code allows and the finest the predator demands, which never happens twice. 1/2in mesh breaks both rules at once. The low eave is protected by the 12in rafter tail. The high eave is not, so the metal roofing and drip edge run 1-1/2in past the back wall plane so water drips clear of an opening that is directly below it. Purdue's ag-engineering sheet is blunt about the reason to shield an eave inlet at all: an unprotected one *can create unwanted drafts in the animal area*, and forcing the air up through a rafter cavity behind a fascia board *helps break up wind gusts*. That is what the fascia and the tail are doing. AND THE BIRDS' TWO SLOTS GET FINISHED HERE. Back wall and front wall, 5-1/2" high, top stud bay, one row of flat 2x4 blocking under each so the slot has a bottom. Trim each exactly like a window: 1x4 casing all round, 1x2 sill sloped out, drip cap over the head tucked under the siding course above. Cloth to the INSIDE face. 533 sq in net at the back, 345 at the front, 877 together, 49 sq in a bird — and both stay open all winter.

THE FLOOR JOIST BAYS ARE DELIBERATELY NOT INSULATED, and this plan would rather argue for that than leave you wondering. Three reasons, in order of weight. A closed insulated cavity directly under a feed store is a rodent nest that cannot be inspected or cleaned, and Univ. of Kentucky names soft insulation as *attractive to rodents and insects as nesting materials*. The open space under this coop is shade the flock uses all summer and the parent design sells it as a feature. And the working answer to a cold floor is deep litter, which is already in this plan — Univ. of Kentucky again: *flocks can do well at sub-zero temperatures if you use a deep litter system.* What the floor gets instead is a skirt that comes off in April. Four panels of 1/2in plywood on 2x2 cleats, screwed — not nailed — around the perimeter, over the hardware cloth the parent already buys for this space. On in November, off in April. It stops the wind washing under a floor that has nothing in it, and because it comes off, the summer shade and the ability to look under the building both survive. The three doors are the weakest part of this envelope and the plan is not going to hide it. A door slab here is 3/4in plywood and nothing else; the walk-in and feed doors together are about 11% of the wall area of this building. They are not built up into insulated sandwiches, because a sandwich door racks, swells and stops closing, and a coop door that will not shut is a worse problem than a cold one. What they get is closed-cell foam weatherstrip on all four sides of every opening and a sweep at the bottom of each people-door — which is most of the benefit, costs nothing, and is the layer everybody skips. One last time: none of this touches the vents. Ontario's ministry factsheet on naturally ventilated cold barns describes *an open ridge that is never closed*, and says that to stop things freezing you *install a heating system rather than reducing or eliminating the ventilation*. Ohio State's dairy ventilation sheet: *during severe winter weather air inlets may be partially closed. DO NOT CLOSE COMPLETELY.* Cornell got there in 1930 — their open-front poultry house's top ventilator door was built one inch narrower than its opening on purpose, because *if this one-inch opening is not provided and the front-rafter ventilator door is closed, frost and moisture will collect on the roof boards.* Ninety-five years, three species, one answer.

A full-height stud wall 36" in from the end wall, closing off a 96" x 36" feed and storage room. Its door to the outside is the one you already framed in the right end wall and hung in step 8b — there is no second door. Feed, bedding, tools, the egg basket and the medicine box all live in here instead of in the house — and because the wall is solid, rodents drawn to stored feed are kept out of the bird space — which means it has to reach the roof. The roof slopes, so the top of this wall slopes with it: the studs run from the low side up to the high side and the top plate is cut on the rake. A partition that stops flat at the low-wall height leaves a 22-inch gap along most of its length, and the rodent barrier you built it for does not exist. This room is not bird space and is excluded from the capacity figure.

18 birds NEED 180 inches of perch at 10 inches each. Why 10 and not the 6 you have read everywhere. Six inches — 15cm — is in EU Directive 1999/74/EC, the UK Welfare of Farmed Animals Regulations, the Canadian NFACC code, the UEP and Certified Humane standards and the USDA organic rule. Eight instruments, one number, and all eight copied it from the 1999 directive. Then somebody measured a hen: Giersberg, Spindler and Kemper (2019) put a perching brown layer's body width at 14.8cm and a dual-purpose hen's at 16.0cm. At 15cm a bird has nothing to spare, so the standards that claim 6 inches lets a whole flock roost at once are wrong on their own arithmetic. EFSA's 2023 review recommends 7-1/16" per hen and that is the only figure here with evidence under it. We build to 10, which clears both. The cut list below BUILDS 219 inches — 3 bars at 73". Those are two different numbers and this plan states both, because a plan that prints the requirement and calls it the built total is contradicting its own cut table. Use a rounded or slightly flattened bearing surface 1 to 2 inches across rather than a thin dowel or a full 3-1/2 inch flat face: it spreads footpad pressure and lowers bumblefoot risk. So mount the 2x4 ON EDGE, 1-1/2 inch face up, and ease the top corners round. Laid flat it presents a 3-1/2 inch face, which is the thing the sentence above tells you to avoid — the bar is the same board either way and the plan has to say which. (One exception, and it is not yours unless you are in hard-freeze country: keepers in deep-winter climates deliberately lay the bar flat so a hen can cover her toes with her breast feathers against frostbite. Below about zone 5 that trade is not worth the footpad pressure.) Set the top of each bar 20" off the floor, 11-13/16" apart, and at least 7-7/8" off the wall. Those last two are not eyeballed: 30cm between perches at the same height and 20cm from a perch to a wall are in EU Directive 1999/74/EC and the UK Welfare of Farmed Animals Regulations, and EFSA derives the 30 from the length of a sitting hen — 15cm of her each side of the bar. Stagger them like stair treads rather than stacking them, so the birds underneath do not get rained on. No bar sits over a nest box. 73" of bar does not hold itself up. Each bar gets 1 leg(s) under it at 36-1/2", so no length of bar spans more than 48" between supports. A roost bar is a 2x4 on edge, and no span table published anywhere lists a 2x4 in bending — which is the same reason the floor under you is framed in 2x6. Wall cleats at the two ends are the whole support on the smaller coops in this line and they are not enough here. Directly beneath the bars goes a removable droppings board — birds put out most of a night's manure while roosting, and catching it on a board you slide out and scrape turns the daily clean into a two-minute job. Never use wire for this: droppings stick to mesh and it becomes impossible to clean.