this shows me it also depends in the chickens, no matter their ages. I tried to have week old with 4 week Olds in a very large run, and the young Cockerels were harassing/bullying/biting and not letting go of the babies.![]()
I've often mixed up to 3+ week age differences in my brooder without issues. The key is to have lots and lots of space. That's pretty much the main constraint for how many birds to have. No one can answer that for you. How many adult birds can you house comfortably, without crowding? How many adult birds can you afford to feed?