We have 4 new EE standards that are five weeks old and 2 mature four year old hens. The hens don't seem to be aggressive toward the small ones, but they haven't been locked together in a confined space. Do you think it would be safe to mix them in a few weeks even with a size difference or am I asking for trouble? If they are fine in the yard together during the day do you think they would be ok at night in coop?