Have you experienced callouses on your fingers after a few days of working with your hands on a tough task? That's what's going on with your roo's toes.
I have two roosters with such overgrowth in their toes. If it appears it's causing discomfort, you can carefully trim some of it with pet nail trimmers. But be careful. There is a blood supply to it, and cutting too much off can result in bleeding.
It seems to be caused by walking on rocky gravel and stone pavers which I have in abundance around my coops and runs. One heavy hen also seems to get these. It's only a problem if it affects their walking.