I received 7, day old bantam chicks on Mar 24th. Three Rose Combs, three sebrights, and one Old English. One of the Sebrights died the day after arrival. A second sebright had pasty butt which I cleaned and appears to be OK in that area. I then treated the little flock with tetramycin for a week removing any grit from their diet. However, that littl, second sebright continues to breathe heavier and more frequently than the rest of the flock and appears to be at least a week or more behind the others in feather growth and size. It has a healthy appetite, drinks plenty of water and is active. It does appear to be cold at times because it seeks to get under the wing or body of the others. Four of the 6 are now outside and doing well here in South Florida. I have kept the remaining chick and a healthy companion inside under the lamp until such time as the little one feathers out a little better. The other chicks are fine. This one appears to be as active as the other ones but behind in its development and still breathes rapidly and heavy. Any idea what might be wrong and what I can do about it?