If they are not fully feathered yet, then I don't put mine outside until it's in the 70's during the day. Bubblesegg, I don't know what you mean by two henboxes. One coop and two henboxes? Henboxes for laying eggs? Have you tried introducing the babies to the adults? In general, almost ALL the hens will not be friendly towards the babies, not just the mean one. I will either fence off a part of the coop for the babies when I move them outside or if I'm only adding a few chicks, will place an old metal dog crate with grated bottom into the coop so that the adults can get used to the babies. Will let them all out together to free range in the evenings and return the babies to the crate at nightfall. If its summer there now and warm at night, then they can certainly go outside. I think it seems to be more of how you're going to introduce them to your adults.