My father and I purchased 25 sex link chicks 2 wks ago. A few days ago one died, but prior to that it began to have a really hard time breathing. Today we have another one that is have difficulty breathing, laying down, eyes are closed, and it has poop crusted on it's bottom. We got antibiotics yesterday and began to put in the water (we didn't do this when we brought them home because we were told by the breeder that they had already had their medicated water and didn't need it). We have raised chicks before but never encountered this, suggestions are needed. Thanks!!!