No - you don’t have to keep them in a brooder for 6 weeks to keep them safe from a predator. My 3 week old chicks have the run of the 8x8’ coop, and will soon be in the run as soon as I get the fence reinforce. As long as the coop and run are predator proof, they are fine.If you want to keep your chicks safe, then absolutely! If they are that small, they can get easily caught by predators.