Your birds will need to h ave all their adult plumage, and this varies within breeds and among birds of one breed. Often bantam pullets will have their mature plumage by 5-6 months. You must open the wings to see any immature feathers on the wings (may be different pattern than the mature feathers). Cockerels should have tails well grown in, and again, no "baby" feathers and you must inspect them for this! Might be 6 months or up to a year to be at their best! CJR