I'm fairly new to this whole chicken thing and I love my girls so so so much. Sadly today one of my first girls had to be killed by my partner. I just want to try and figure out what was wrong with her and hope that my other three are going to be OK. Sarah was fine this morning when I let her out of their pen for a free range. This afternoon when I went to go and feed them their favourite treat, vegie scraps bread and chilli, I found Sarah hunched over in the corner of the run with mucus hanging from her nose. I picked her up and she was really lethargic. She walked over the food and tried to eat but couldn't seem to get the energy up to do it. She just walked really slowly back to the side of the run and lent against the door. She was opening her eyes really slowly as well. About 3 months ago she moulted and has stopped laying really ever since. I'm not sure how old she is as I adopted her but she was my only egg layer as I have one brooder and my other 2 are only babies 4 months and 8 months. I'm so worried about them all now what do you think it could be??