help, my 3 year old RhodeIsland Red hasn't been feeling herself for about one week. Her comb is floppy and not bright. Her crop looks swollen but feels like it is full of air. She is lethargic, standing around and falling asleep standing in the yard. She has been separated from the other chickens. I have tried feeding her chopped eggs. After eating a small amount, the chicken is stretching her neck out.?!. I also gave her yogurt and water with apple cider vinegar. The other chickens are not exhibiting any symptoms. I can't find a vet who will treat my chicken☹️ Any ideas what is wrong with her and recommendations on how to treat her???