Seems like his breathing was affected too, like he was congested. It's usually not the blackhead itself that kills the bird, but all the secondary infections, E coli, Coccidiosis, Respiratory infections.
Here is one article on byc you can check out. It has treatment dosage in it somewhere.
https://www.backyardchickens.com/th...eird-head-turning-thing.891387/#post-21348940
Here is one article on byc you can check out. It has treatment dosage in it somewhere.
https://www.backyardchickens.com/th...eird-head-turning-thing.891387/#post-21348940