Lethargic Chicken can't walk, losing weight

[SCchickens2011]

I have a 4-5 yo barred rock that has suddenly developed an issue. Well maybe not so suddenly. I first notice about a week or two ago that the middle toe on her right foot would curl in to the inside toe when she walked. Now she can't walk, she just lays there on her side and she has lost weight. Her comb is still nice and red, but she doesn't eat much and we gave her some antibiotic water yesterday by syringe and free feeding. I have her separated from the rest in her own "box" in my laundry room cuz the garage is too warm. I noted that she does had slightly offensive smelling poo, but I think the really smelly smell is coming from her legs, they look like they are crusted over and maybe infected? she doesn't have an impacted crop, I checked that.

I have had a lot of losses the past two - three weeks, I have lost 4 chickens to seemingly various issues. They were all my older girls of about 4-5 yo.

First was a RIR found dead in a dirt bathing hole behind the hay stack. No idea how long she was there but maybe less than a day, she was still limp. Next was a GSL she had maggot looking creepy crawlies coming out of her butt but after death they were not there. I deep cleaned my coop and run after that and gave everybody an individual syringe fed dose of Fendendazole goat de-wormer. Then another RIR a few days after that who seemed to have peritonitis, and lastly was the other day another BR that started to look like she had peritonitis, she was labored in her breathing and her comb was purple, when I tried to syringe feed her antibiotics she ended up vomiting this smelly greenish fluid and it had like seedy looking stuff (possibly partially digested meal worms) in the greenish fluid. The next day she died. Now this one... what is going on???? Is it just age taking it's toll or something else???Any ideas?

Also where she is, I also have my new chicks (3-4 weeks old), but they are in their own brooder box and there's about 5 feet of area between where she is n where they are, will they be okay??? Does anyone think it could be an airborne issue? We don't touch anything after we have handled her until we have washed hands and arms thoroughly with hot water and antibacterial soap!!!

 

[Eggcessive]

Maggots can cause fly strike in wounds or when droppings are soiling the vent area, so keeping them cleaned and trimmed if necessary is important in warm weather. Can you post a picture of the BR's legs? She may have scaley leg mites or a staphylococcal infection. If you lose another chicken, you may want to consider sending the body off to your state vet for a necropsy. Since you have a possible unknown illness, I would keep the new chicks away from the older chicks. Put your chickens on some poultry vitamins, incase of a deficiency. Check to make sure that your feed is fresh dated, since older feed can lose vitamins and nutrients.