Buff Orpington acting lethargic

Good afternoon everyone,
I just found my 21 month old buff orpington hen sitting in the straw by herself. That is unusual for her. She didn't run for treats, rather very slowly walked to the others and didn't try to eat their treats. I tried offering her meal worms which she turned down so I knew something was wrong. I checked her out best I could; no parasites, not egg bound, her eyes and comb are bright, wings and tail not drooping, everything feels normal. They were wormed five weeks ago with Safe Guard. Her crop is empty and it's 2:30 in the afternoon. I don't know if she is laying. I have three BO and three Rhode Island Red - the RIR are molting (in April). I am getting between two and five eggs a day, once I got six. I have one hen who is still recovering from a year-long illness so doesn't yet lay regularly. So far today I have three eggs. All of the other hens are acting fine. Yesterday I scrambled them one egg each of the frozen eggs left over from last winter . Must have been too much because I had a mess to clean this morning, they all had runny droppings. Could that cause a problem? I don't know what else to check and hope the experts out there can give me more information. Thank you

Well, don't know what was going on but the problem seems to have cleared itself up. Maggie is up doing chicken things, her crop is full and she is running around. Real odd but I'm glad she is better. Now hoping she is OK in the morning.

Sorry that you didn't get any answers earlier, but glad to hear she is all better. Sometimes chickens act like that during a molt. Has she just come out of her first big molt?

She finished a light molt early last fall and isn't molting now. I was afraid of what I would find when I let them out of the coop this morning but she is fine thank goodness!