I just set another batch of eggs in the 'bator so my current babies will need to vacate the brooder in three weeks' time. At that point they will be just under 4 weeks old. They are already outdoors during the daytime and their parents visit them off and on throughout the day with calm curiosity. When I was bringing them in to bed this evening, I set the box I carry them in down in front of the rooster and one of the hens. They seem to understand that the chicks are their babies but aren't quite sure what to do with them. It seems to me that I should have no trouble when the time comes, but I'm curious: what's the youngest successful integration you other byc-ers have had?