How is your turkey doing? My experience is that once turkeys are adults, they develop a more robust immunity against Blackhead. However, that does not mean they can't get it when adults, especially if they hadn't previously been exposed to it before. The very first signs of blackhead in a turkey even before they start having the tell-tale sulfur-colored droppings, is they will stop eating and stop trying to keep up with the other turkeys. Toms will stop strutting and gobbling, hens will stop yelping and putting, and they stand off from their group and may even appear sleepy and nap a lot during the day. At this point, I begin treatment, long before the sulfur-colored droppings, as the sulfur-colored droppings are a late symptom of disease in Blackhead, indicating they have begun to have disease in their liver. Metronidazole is the off-label treatment for blackhead at a dosage of 30-60 mg/kg per day for 5 days. In late-stage illness, it may be beneficial to also dose with enrofloxacin to combat any secondary bacterial infections.
From my experience, if you intervene and treat early, the birds have a complete recovery with no long-term sequela from the infection. I have butchered a bird who was treated for blackhead as a juvenile and his liver was immaculate and perfect, so early treatment prevents long-term liver damage. I personally will eat a bird that had been previously treated with metronidazole, even though the drug has not been approved by the FDA for use in turkeys used as meat birds to be consumed by humans. That is only because it hasn't been studied for use in turkeys to treat blackhead, so there is no evidence-based research (yet). However, metronidazole is used to treat various illnesses in humans, so in my opinion it is safe, and we eat the birds. Mind you, when we eat them, they have been off metronidazole for many, many months. (For the record, I am not recommending anyone eat turkeys treated with metronidazole, only stating that I do use them for my own personal consumption but we do not sell turkeys for meat. So use your own judgement and make your own decisions.)
The mortality rate of blackhead without treatment can be upwards of 90-100%. I have a friend who had an entire group of juvenile turkeys that all contracted blackhead and all but 1 died as she did not intervene and did not know what was going on until it was much too late, so they can occasionally fight it on their own and pull through as her only remaining turkey did. We verified it was blackhead that killed her turkeys by necropsy performed by me.
Sorry for the long post. It may be too late for your turkey if the bird did in fact have blackhead, since this post is over a month old. But if nothing else, this information may prove useful to someone in the future.
