The only things I know about scaly leg are:
(a) Victoria Roberts says you use white spirit, dip the whole leg (both legs) and you have to do it several times until it is cleared up. And again if it comes back. And again...
(b) friends who breed different breeds each year and supply eggs to their locals all year round, and know a lot about poultry, in the end got rid of all their birds, burnt all their housing, built everything from scratch and since then have only ever brought eggs in, never ever again live birds.
Sorry I don't know whether the thing you describe on the neck is scaly leg or not. Hopefully someone more knowledgeable will be along shortly.