Well the cocci treatment did nothing. I guess it's time to acknowledge that I have a Marek's flock.
I guess it's time to get some labwork done. There are hundreds of things that can afflict chickens just like other animals. Coccidiosis and Marek's don't resemble one another. I know people on here are quick to blame coccidia when chickens are sick but virtually every chicken will have coccidia in their system. It doesn't mean they're in danger from it.