I have three 10 month old female chicks. At age 4 months I introduced them to 3 more 8 wk newbies. I first separated them by a wire fence day and night for 6 weeks, then we introduced them together only during the day for weeks, then into the coop. The three newbies stayed together outside for a long time, then they wanted to make friends with the older girls, but the older girls didn't want anything to do with them, just kept to themselves. Then finally they all seemed to be getting along except during treat time the older ones would chase them away. Anyway, it's been 5 months and now the older girls are biting the newbies when they eat and I give them treats. They never bit them before, what's going on. Has anyone suddenly had their chicks decide to bite the newcomers after such a long time of no biting?