I have some 3 week old Cornish cross that are really starting to grow some feathers. The bodies are mostly covered, but the heads still have some baby chick down to them. I currently have 22 of the cornish x's in an 8x10 pen inside my barn. It has 3 foot tall side walls all the way around and chicken wire above that. There are no drafts at chicken level, but plenty of air movement above. They do not have access to the outside and are confined to this pen. As they grow I will move them to a larger 10x15 pen. I feel like 22 butchering size birds in this pen will be plenty crowded. I have two 250w red heat lamps hanging in this pen and the birds seem to congregate at night under the lamps. Temperatures this week are ranging from 30-50 during the day and 20-45 at night. I feel like they need heat for at least another week or two, but this is also my first batch of chickens. At what temperatures/age do you normally remove heat? I can give them heat lamps their whole life if needed, but if I can turn them off sooner, I am all for it. Reducing fire risk and power consumption will be nice bonuses to turning the lamps off.