We have been given an old tortoise shed which we are converting into a chicken coop. It is 6' x 10', and slopes from about 4' to 5.5' tall. One 6' side has a human door, the full height of the shed, the other 6' side has a window and a tortoise door which will become our chicken door to the run. Aside from ripping out the insulation, we only need to add ventilation (that thing was airtight!), nest boxes and perches. The window is about 18" tall by 28" wide, and it starts maybe 3' from the bottom. We've taken out the glass and added hardware cloth. We have also taken off an 18" x 8' panel of OSB from along the top of the tallest 10' side, and covered that in hardware cloth too. We have 10 seven week old chickens, and may (hopefully) be getting 2 - 4 more this month that are already laying. My question is about positioning the perches. How far from the ventilation do they need to be? Will it be too drafty if the chickens are roosting a few feet from an open window, at the same height? Do we need to be able to shut the window? (We could put the glass back in at night.) The window is toward the taller side of the coop, so we were thinking about running a perch the full length of the coop on the shorter side. Also, is that enough ventilation? And would it be enough even if we closed the window? We could add more easily enough, the problem is just positioning it. Thanks.