Part of heat control is letting the heat get away, rather than building up. Ventilation is key, but you have to look at where the heat is coming from. Is it the roof and south wall? Insulate, insulate, insulate. Make a mirror and reflect it away. Paint it white, and use aluminum.
I put roof ventilation channel between the rafters of my coop, with foam-board insulation between that and the coop, and soffit vents at both ends. The roof gets freakishly hot on sunny days, but instead of acting like a toaster coil warming the coop, the heat is carried away by ventilation before it even gets inside. My coop stays surprisingly cool on hot days.
Aluminum faced foam is better for reflecting heat (either keeping chicken-heat in, or sun-heat out) than plain bead foam or fiberglass. You don't have to use it everywhere, just where it's going to do the most good. You can also staple cheap "store brand" aluminum foil to the interior of the siding before filling the stud bays with ordinary insulation.
Another thing I did was extend the roofline on the south so that it shades the south wall. On June 21st, at noon, there's an inch or so of shade on the ground in front of the coop - not a bit of sun shining on the wall. But in the winter the sun shines on the wall and through the window to warm the inside of the coop quite nicely. Basic passive-solar design.
I put roof ventilation channel between the rafters of my coop, with foam-board insulation between that and the coop, and soffit vents at both ends. The roof gets freakishly hot on sunny days, but instead of acting like a toaster coil warming the coop, the heat is carried away by ventilation before it even gets inside. My coop stays surprisingly cool on hot days.
Aluminum faced foam is better for reflecting heat (either keeping chicken-heat in, or sun-heat out) than plain bead foam or fiberglass. You don't have to use it everywhere, just where it's going to do the most good. You can also staple cheap "store brand" aluminum foil to the interior of the siding before filling the stud bays with ordinary insulation.
Another thing I did was extend the roofline on the south so that it shades the south wall. On June 21st, at noon, there's an inch or so of shade on the ground in front of the coop - not a bit of sun shining on the wall. But in the winter the sun shines on the wall and through the window to warm the inside of the coop quite nicely. Basic passive-solar design.
