I got 3 BO chicks 10 days ago and they were identical in size. One was just a shade darker in color, otherwise I could not tell the three apart. Now 2 of the chicks are much larger and have quite a lot of feathers on the wings and some tail fluff. The third is much smaller and just barely has feathers starting in wings. All of them eat and drink and run around very happily. Would the difference in growth rate indicate male/female or could the one have a problem I cannot detect? They were straight run chicks. Any thoughts?