That really depends on how many chicks size of brooder outside temp etc. Also, depends on where they are going after the brooder. Can you provide a heat lamp once you move them to the barn or where ever they are going next? I keep mine in the brooder for about 3 weeks, then they move to a pen in the barn separate from the other chickens but with a heat lamp. Once they are about 6 weeks they move to another section of the barn without a heat lamp (depending on the weather of course) then once they are about 10 weeks they go into the general population so to speak. I hope that helps???