How much scratch in proportion to layer feed would you say you feed? If you're feeding a mixed gender flock, it's a much better idea to feed an all flock feed with calcium on the side for the hens. High levels of calcium can cause kidney damage in chickens that don't need extra calcium and could contribute towards gout.
ETA: Layer feed also has a lower protein % than what roos need. I don't have a roo, but it seems like it would be simpler and less worrisome to feed an all flock feed to hens and roos alike with crushed eggshells on the side in a separate dish for the hens.
Sorry to get this thread off track, but his symptoms could be partially induced from the excess calcium/kidney damage from the calcium.
https://organicfeeds.com/can-roosters-eat-layer-feed/
https://ucanr.edu/sites/poultry/files/186894.pdf