I got two chickens for my birthday this year, in June, they have been great up to now but today one of them is very poorly, I think she is probably dying. She seemed absolutely fine yesterday but today she seems to be unable to walk and laid down outside in the covered bit of her coop, she didn't go inside when it got dark like she always does. I picked her up and she just bowed her head and closed her eyes. I've brought her indoors and put her in an open top crate on a towel. She is still breathing but appears very weak. My other chicken seems unaffected so far. Any ideas greatly appreciated, it's pretty sad.