Can I mix 4 week old chicks with 5 week old chicks without complications? It may seem like an academic question but I have never done it before I always do a slow introduce with all new birds.
Ive only mixed 1-3 week olds.
Somewhere I read when they hit around 4 weeks, problems begin with being territorial, etc. Before that, chicks just dont care.
Thats just being general. I myself would maybe try putting them all together in an unfamiliar coop and monitor.