I've been doing so much research that I think my brain is going to explode! I highly doubt that it was Marek's. The only symptom even close to Marek's that she'd shown was not being able to walk without falling over. She was able to stand still, on both legs, perfectly fine. But if she went to walk it was like watching someone that just drank one too many shots at the bar. Before Saturday she was able to peck the ground, eat, & drink perfectly fine, even though since she was a chick she always would perch with her head tucked in more than anyone else - she looked like she didn't have a neck, though she did. Since she had sour crop she never was nearly excited as the others about waking up in the morning, going outside, & eating treats. When I first got the original 15 they were only a day old & I started them on medicated chick starter. When they were exactly 2 months old I bought 2 roosters that were about the same age, & 1 hen that was about a month younger from a breeder. Since then, they were all kept together, I didn't get anyone new, & we don't visit any other flocks. They're kept in a 10 x 10 horse stall at night (now there's 15 hens & the 2 roosters), and free range during the day (with more than enough land, as long as they share nicely with the horses!). I think that she had sour crop when she was about 4 months old, my memory isn't the greatest, but it was shortly after Olive had an impacted crop.
I've read some people having similar issues due to lack of protein &/or lack of vitamin B. Could this have been the problem? Everyone when thru a heavy molt & are just now starting to lay again. I feel horrible thinking that if I had paid a little more attention I could have given her some dried cat food &/or added vitamins to their water. I've used Poultry Protector on them twice, and have used an equine fly spray (Ultra Shield EX) in their stall twice. I also have put down DE, which they have enjoyed as a dust bath. Around November I have them Rooster Booster triple de-wormer.