A little over two weeks ago, we bought five pullets from a reputable breeder who we have bought chickens from before. On the way home, I heard one of them sneezing. Turns out, all of them were sick and three died within the first week. They had runny noses (beaks?), eyes, and labored breathing. The remaining two have been treated to five days of Tylan in their water. Their runny noses have cleared up and they appear to be a lot perkier. So, they seem healthy. My question is---can they now be added to our existing flock? We did not have a necropsy done on the birds that died and our breeder claims that he has not seen any signs of illness in his birds. So we don't know what disease we were dealing with. Oh, did I mention that the larger flock we have belongs to our 10-year old daughter and one of them is the grand champion Bantam at our county fair this year. Yeah, so we really are unsure about what we should do at this point. Any advice would really be appreciated.