I notice a common thread running through all of your afflicted chickens - symptoms of mold ingestion, not enough to kill them outright, but tiny amounts possibly, such as they would get by nibbling something that has mold on it. A spoiled spot on a piece of fruit that they found on the ground, or a scummy puddle, or a moldy leaf. Just enough to set up a toxic reaction and cause yeast to start growing in their crops.
The crooked neck symptom could be from wry neck, but since more than one has it, it would be more likely yeasty crops.
The limping can also be from mold ingestion, a mild lameness which is also a symptom of mold toxicity.
To treat the multiple chickens, the easiest way is to substitute copper sulfate solution for their regular drinking water. Or you can treat individually with miconazole.
You do need to do some sleuthing and find the possible mold source to be sure this won't be an ongoing problem. It doesn't take much mold to trigger yeasty crops.
The crooked neck symptom could be from wry neck, but since more than one has it, it would be more likely yeasty crops.
The limping can also be from mold ingestion, a mild lameness which is also a symptom of mold toxicity.
To treat the multiple chickens, the easiest way is to substitute copper sulfate solution for their regular drinking water. Or you can treat individually with miconazole.
You do need to do some sleuthing and find the possible mold source to be sure this won't be an ongoing problem. It doesn't take much mold to trigger yeasty crops.