I have a chicken that recently began keeping tail down but eating and drinking. Stayed away from other chickens but her poo looked fine. About Friday she stopped roosting. It looks like a large bump on her back where tail droops. I have done butt check but do not feel any eggs. Since Friday Her poop is very very tiny but looks fine. She has stopped eating and drinking today and just lays and pants. Her back end contracts like she us trying to poo or lay an egg. ...I have given her Big Ole Bird PROBOTIC and I made her food a mash. I fed her some scrambled egg yesterday and she ate that. They are on a good layer feed with calcium in it so I have not given and free eat calcium. She is a 3 yr old Delaware. They free range in back yard. Coop is kept very clean and food and water are available both inside and outside my coop. Any Suggestions? I am guessing to put her down this eve if she does not improve today. She has suffered enough. I have searched internet but can't come up with anything that might cause this. When noticed her illness I brought her in. Second chicken this month. The other one was a 4 yr old Brama. I don't feed but meal worms in eve for treats. Thanks for any help.