I purchased 20 chicks in October, knowing it is not the best time of the year to do so. They all survived chickhood, but since moving to coop in December I have lost 5 to unknown illness?? This first chicken I think had a broken leg and could not get to water and food enough. Seemed very weak was laying on her side with her feet straight out. The second I thought had wyr neck. Her neck was twisted under her. I feed her for two days out of a small dish and she did better for a little while then passed on the third day. At this I started with a powder antibiotic in the water of all other hens. They have not started to lay yet, as I live in NJ and it is very cold now. The other three just were curled up and dead when I went in the coop in the morning. No signs of being ill. The first round of antibiotics was not complete. I started another round (it says not to give more then 14 days) and 14 days will be on Tuesday. I had grown up with chickens and my grandparents were chicken farmers and have never had this many die so close together. Do they need to be outside? Can it get too cold (this past week it was about 7)? Should they not be on dirt floor? I ask my grandfather these things but he is of the old school mindset and says everythings is fine. Is this normal for buring chicks in the fall instead of spring. Any help would be greatly appreciated. I feel like I am failing at this and really don't want to loose any more chickens.