Chicken seems lonely and not eating

[Just Pam]

Thanks for any help you can provide. I have 6 female chickens about 9 months old. Got all of them at the same time. Everything has been fine till about 3 weeks ago. One of them just started going off by herself and not eating alot. She quit laying eggs and just stands around. I took her to the vet and they didn't seem to find anything but they gave her a B12 shot, and I have given her Metronidazole, and Panacur. Vet said to keep her separate for a week which I did. She got some what better and I put her back with thr rest of them. She started walking more but a couple of the other chickens would peck at her sometimes. Now she is back like before. She stands in the run byherself she won't eat what I put out. Some of the other chicks push her away from the food sometimes. She won't eat out of my hand. She just goes looking for food. She hasn't laid in 3 weeks. She just stands around fluffed up.( It has been in the 50s-60s during the day) the rest of the flock is doing get. She has always been a happy chick. Any help? Thanks

 

[Wyorp Rock]

What's her poop like?

Does she have canker? Metronidazole can be used for other things, but it's commonly use to treat canker in birds.

Feel her abdomen for any bloat or fluid, re-look her over for lice/mites, see that her crop is emptying overnight.
Panacur depending on the dose and duration should treat roundworms and other worms - did the vet do a fecal float to see if there were worms and/or Coccidiosis?

Not laying and being fluffed up, she may be having difficulties with a reproductive disorder.

 

[Just Pam]

Her poop looks ok. Before getting the medicine she seem to not poop much. The vet. gave her the meds to cover her since we couldn't find anything. The vet didn't do a fecal float. Didn't think about a crop. I'll check it in the morning. Never done one. Her meds were Panacur .05mls once a day for 3 days. Metronidazole .9mls. twice a day for a week. She seem to feel better and pooped more after the meds. But back to not eatting well. And not laying. Thanks for your response.