Chick not growing in size, but wings developing

[friedbluebanana]

I have five little chicks that are about two and three weeks old. The Silver Wyandotte does not seem to be growing in size, and is way smaller than the others. However, the feathers on her wings are developing. Her wings are almost longer than her body. She seems to be acting normal - she eats, drinks, and runs around with the others (though she is often getting stepped on by the bigger chickens). These are my first chicks so I would appreciate any input