I came home tonight and found one of my chickens lethargic. She is almost 3 months and shares a coop with 4 others. She just wants to lay there and tuck her head. I see no signs of obvious injuries except for some feathers missing from her back. But no injuries or redness to the skin. Her crop doesn't appear to be full. Her skin appears normal and no unusual color changes or black specks. When she did walk she was unsteady. She did eat a little and drink a little. I have her seperated with food and a water electrolyte solution. Please help. Any ideas?