I think there is often more to the story when they have impacted or sour crop, especially if the cause is not obviously phsical, like a crop full of straw. I base this on some things I've read from some "old timers." I don't have a "magic cure" for you, but I'd concentrate on things like probiotics, ACV, whatever you think may help her gut heal or soothe it. Antibiotics may belp if there is an intestinal bacterial infection, but I'd be sure they get probiotics after, to help rebuild normal flora in there.
Just on the chance you don't know, chickens (well, birds) don't make lactase, the enzyme needed for digesting milk. Fermented products like kefir shouldn't require lactase.
Gapeworm would be unusual, but certainly posssible. If they have it, you can swab their throat with a Q tip and one or some will be on it when you remove it. They are about 1" long, reddish and very skinny.
Just on the chance you don't know, chickens (well, birds) don't make lactase, the enzyme needed for digesting milk. Fermented products like kefir shouldn't require lactase.
Gapeworm would be unusual, but certainly posssible. If they have it, you can swab their throat with a Q tip and one or some will be on it when you remove it. They are about 1" long, reddish and very skinny.