I've had it happen before with roosters, especially brahmas. The males feather in much much slower.
Might just bee a real slow grower. looks almost like the runt of the litter. I've bought a few that took awhile to feather out namely my barred rocks. Also my rooster ee is taking longer than my 3 hens did not sure if it's the barring or just wanted to take his time. Should be fine just make sure has plenty of food feathers take a lot of protein to make.
Look at those smart little stinkers on the roost already.. love that lil one on the end just hangin out.