I have 3 orpington hens 3 years old. Big girls. They free range. The first of March I got 2 each of speckled Sussex and Australorps-4 weeks old. I have been keeping them in kennels in the garage until they get big enough to run with the big girls. But sheesh it doesn't seem like they will ever be big enough. The Sussex are supposed to be 6 lbs when grown and the hatchery said they would mix well with the orpingtons. I am not as concerned about the australorps because I think they will be ok. They are Australian orpingtons anyhow. They are all growing but the australorps aren't half as big as the grown orps and the Sussex aren't even as big as the australorps. I just hate keeping them in a cage albeit a big one. I sit with them some during the day and pull the cages out on the driveway when weather permits. But the orps can be aggressive sometimes especially when it comes to food. Plus these little ones can fly! I clean their cages every day and they hover around the door, seeming to be looking for a way to escape. How big should they be before I try integrating them do ya'll think?