Sick chicken unknown cause

[ShellBee123]

A second hen of mine has become ill, both cases are a month apart so I didn’t think it was contagious until now. Symptoms include lethargy, falling over to one side, lack of appetite, tail pointing down, and runny poops sticking to her fluff. They are (were) both my older hens, about 3 or 4 years old (we ended up culling the first one after her condition didn’t improve). They don’t appear to be egg bound, that was my initial thought, but no hard lumps or anything that I noticed, but they both seem like they’ve lost weight.

Things I’ve done: isolation, vitamins and probiotics in water, dewormer, and epsom salt baths.