The coop has four walls (double layer with an air pocket in between), the floor is waist high off the ground with a hole in it off to one side for the ramp to come up through, and a wire mesh ceiling with polycarbonate panels 20cm above it. I can put cardboard or plywood temporarily over the mesh at night to keep a bit more warmth in, and will be installing a sliding cover for the ramp opening to reduce drafts coming up from below if needed. The babies are spending their days in the enclosed run at the moment and in a week or so I'd like to start putting them in the coop at night as well once they've feathered out more but wonder if it will be warm enough. As long as the coop is kept dry and draft free and I have a good layer of litter/shavings in there will 5wk/6wk old babies be OK in there? It is getting quite warm here during the day (mid-summer, temps averaging a 65 - 68 low at night and up to 86 - 90 during the day). I will get a thermometer to see if I can find out what the temp is inside the coop at night, but any opinions or tips in the meantime would be great. Thanks!