I hatched out some english lavandar orps earlier in the month. I then hatched out some EE, whent he EE hatched the orps were already at 3 weeks, I tried just tossing the day olds in, but the older birds started to peck and give the lil sleepys a hard time. I ended up putting the day olds in a smaller tote that could sit directly in the brooder. This let the birds get use to each others sounds and since it was a clear tote, I think they could see each other a bit as well.
After about 3 days I removed the tote and have had 0 issues. the birds are all great friends, even though the orps are a good bit bigger. They are so big, they are about to go into my basement for hardening and to enjoy the 4x8 growout pen I have made for them