I just had to put my almost three week old cockerel in juvy! Yes, three weeks...ugh! He was aggressively pecking one of the other cockerels. It worked! He hated being seperated.
Oh lol XD we only have 3 hens and him, but we don’t exacly have anywhere to put him (besides a VERY small Bunnings version of a coop that isn’t big enought