I got my second batch of chicks 2 days ago. Everyone is eating and drinking normally and they are very active. Saturday night I noticed that one of them was making a crackling sound. It's only noticable when you hold her near your face and she seems to be otherwise healthy. This morning I picked up a packet of oxytetracycline but I'm not sure if I should give it to her because when I picked her up to listen to her the crackling sound has lessened alot. Should I still medicate her? And if so, should I also medicate the other chicks in her brooder? Right now all of the new chicks are seperated from the ones I got a week and a half ago. She is around a week old and is on sand bedding.