Blackhead (histomoniasis) and trichmoniasis (canker or frounce) are two different diseases, but both can be treated with metronidazole, dimetridazole or ronidazole. When treating for blackhead, one must *also* treat for the cecal worm with something like Safeguard or Valbazen.
To treat cecal...
Her poop looks pretty normal to me. I think I would *also* worm her with Safeguard liquid or paste at 0.23ml per pound for five days. That amount will treat roundworms, cecal worms, gapeworms, capillary worms and possibly some species of tape worms. Was she vaccinated for Marek's?
-Kathy
Any chance you can take a poop sample to a vet and have it checked for coccidia and worm eggs? Be sure to check her very carefully for lice and mites.
-Kathy