I have 15 16-day-old pullets, and most of them have grown long wing feathers and are beginning to grow body and tail feathers. One chicken however has short wings and no sign of other feathers coming in. Her comb and wattle are on par with the others and she loves flapping up to perches, pecking at stuff, and eating as much as the next chicken. She seems a bit smaller, but not much- it could just be that the others' wings make them seem larger. Is something wrong with her?