Deformed with fenbendazole about 1mo ago, just one round. We actually had to treat the whole flock for winter mites at the beginning of January, so I can confirm that's not an issue.
She's started on Corid as of this afternoon.
I'd re-check again for mites and lice.She is not eating much or drinking much while inside right now.
Check her crop. Work on getting her hydrated and get the Corid into her.
She has a lot of urates, which could point to dehydration, but I'd still get Calcium into her as well just in case she's having trouble expelling a membrane or possibly lash material.
She may have reproductive problems or has laid internally, hard to know.
Hopefully she'll turn a corner.
Keep us posted on how she gets along.
I'd treat for Coccidiosis, but I'd also give her extra Calcium for 3-5 days. You can find Calcium Citrate with D3 at stores like Walmart, CVS, etc. Just pull down on her wattles to open her beak, pop the tablet in and let her swallow.
Re-check for lice/mites and see that her crop is emptying overnight.
Corid liquid dose is 2tsp or Corid Powder is 1 1/2tsp per gallon of water given as the sole source of drinking water for 5-7 days. Don't add any extra vitamins or supplements that contain B1(Thiamine) to their food or water during the course of treatment.