diarrhea in my chicken, still eating, walks slowly but runs when needed

[MychickensandI]

My chicken has had diarrhea for few weeks now and, although she is still eating and wonders around with the flock, I see her fluffed up huddled in a corner sometimes. She will run with the flock but otherwise walks more slowly than usual and I think it hurt her for me to pick her up. I have treated her for worms but it doesnt seem to have helped.
Im in the UK.

 

[Eggcessive]

How old is she? Is she losing weight? Has she been laying eggs recently? Is there any evidence of feather loss or molting? Have you seen any soft or shell-less eggs in the nests? Reproductive disorders and infections or cancer may be common in hens over 2-3 years. Is her crop empty first thing in the morning, and then filling up during the day? Look her skin over for any lice or mites on her skin. What did you use for worming? Flubenvet is a good one in the UK.

 

[MychickensandI]

How old is she? Is she losing weight? Has she been laying eggs recently? Is there any evidence of feather loss or molting? Have you seen any soft or shell-less eggs in the nests? Reproductive disorders and infections or cancer may be common in hens over 2-3 years. Is her crop empty first thing in the morning, and then filling up during the day? Look her skin over for any lice or mites on her skin. What did you use for worming? Flubenvet is a good one in the UK.

Thank you for your reply.
She is about 5 now and hasn't layed in about 2 years. Feathers are fine, no loss that I can see. I will check her croop and her skin for mites. I appreciate the advice.
Yes I used Flubenvet.