I've mixed ages and sizes (LF/bantam) without problems personally. but 2 weeks is the furthest out i'd go.
the range i've had most recently, i had 2 dorkings hatch on thanksgiving day, with 8 cochin bantams. 4 more dorkings hatched a week later, followed by 1 lonely little dorking girl. I worried about the size difference, but she cried and cried all by herself. so i put her in with her bigger sibs and she settled in immediately. then when my next hatch came along another week later (dec 17th) I felt they were too small to go with the nearly 1 month old guys, so I put 'little girl' with the 5 newest chicks (also dorking). The most recent 5 are now by themselves, as I felt they weren't quite ready to go to the outside brooder, but 'little girl' was going stir crazy in the brooder tub, trying to get out and play with everyone else. they get play time on top of the brooders for some exercise and socialization, but if i openned that tub everyone else would hop on in and check it out LOL. so now the 5 youngest are actually the 'grownups' of the play time now, and learning all about mealworm treats.
the range i've had most recently, i had 2 dorkings hatch on thanksgiving day, with 8 cochin bantams. 4 more dorkings hatched a week later, followed by 1 lonely little dorking girl. I worried about the size difference, but she cried and cried all by herself. so i put her in with her bigger sibs and she settled in immediately. then when my next hatch came along another week later (dec 17th) I felt they were too small to go with the nearly 1 month old guys, so I put 'little girl' with the 5 newest chicks (also dorking). The most recent 5 are now by themselves, as I felt they weren't quite ready to go to the outside brooder, but 'little girl' was going stir crazy in the brooder tub, trying to get out and play with everyone else. they get play time on top of the brooders for some exercise and socialization, but if i openned that tub everyone else would hop on in and check it out LOL. so now the 5 youngest are actually the 'grownups' of the play time now, and learning all about mealworm treats.
