We moved our 7 bantam chicks out to a 10' x 12' brick enclosed building 2 days ago. It has a wooden floor, covered with about 4" of pine shavings. It stays fairly cool compared to outdoor temperature (100 yesterday) and is well protected and the brick holds the warmth at night (70ish at night). We haven't installed a roost yet, but it's a priority! Anyway, There are 2 open windows (covered by hardware cloth) that allow sunshine in, and some airflow, as well as a fan on a timer to help circulate the air during the day. I was sitting out with them today for about an hour, and when they got used to me being there, they all started to chill out and lay down. They all chose to lay in the sunshine, and would stretch one wing and leg out (the same side) as they fell asleep. Are they comfortable? Are they too hot? They weren't panting...
