I brought home 12 chicks a week ago today. I don't know exactly how old they are, but they had just arrived at the store that morning. All of them now have several rows of wing feathers, some are starting to get feathers on their backs and all but one have tail feathers of some sort. My all yellow EE chick is the one that doesn't have any developing tail feathers. She also seems smaller than all the rest of the chicks. She is my cuddliest girl. This is my first year raising chicks. Should I be concerned that it is taking her longer to feather and that she is smaller? Thanks!