Got 6 pullets 4weeks ago and up until now everything has been ok. Yesterday I noticed one was laying down a lot, but didn't think anything of it as it was quite humid. Just been out to lock them up for the night and one is laying the coop floor, beak open and looks like she is gasping for air. Her comb looks slightly black on the tips. When I walked in the coop she attempted to move but looked like it was a struggle, she tried to flap, in what looked like an attempt to get up on the roost, but just layed back down in a corner in the coop floor. She is about 24 weeks old, and I believe she hasn't layed yet. What could be wrong with her? Can anyone please advise me as to what I need to do? I have had chickens for quite a few years now, but have been lucky that they have all been healthy. UPDATE: Went to the hen house to separate her from the others, in a separate pen, that is within the hen house, and she couldn't stand, her legs just flopped behind her, she scuffled for a few seconds to try and pick herself up but she couldn't. I won't be surprised if I find her dead in the morning.