About 3 weeks ago, I bought 2 Rhode Island Reds and 2 Australorps who were 2 weeks old at the time. Sadly, last night I lost one of the Australorp chicks. Early Yesterday afternoon, I noticed that she had lost her balance and couldn't walk without falling over. She was still attempting to eat, albeit sitting to do so, but drinking very little. It got worse as the afternoon went on, to the point were she could not keep upright sitting down and keep rolling onto her back and side, and her legs didn't seem to be in her control at all. I took her to the vet, who gave her antibiotics and kept her through the night to give her another dose. Unfortunately, she didn't make it. The vet thinks that she might have had a chest infection, and she was definitely very small compared to the other three. Looking back, she wasn't gaining much weight or growing much, certainly not at the same rate as the others and she wasn't developing feathers as quickly. My main concern now is that the other three stay healthy and don't suffer the same fate, because I truly adore them and don't want anything further to go wrong. They're kept in a brooder (massive plastic storage container) with an infra-red heat light, lined with paper towel and shavings with their feeder and water. I change all this morning and evening to keep it clean and fresh (well as much as the little tractors will allow a clean house). I was wondering if anyone had had a similar experience/could give me some advice as I'm quite new to this?