Should have mentioned, that triangle varies, some boys only have the fringe on a normal feather center, but others have a deep 'V'. With pure white feathers it can be very hard to spot except at close range, often you'll notice extra shine before you see the male feathering responsible. However his tail is almost a gender indicator in itself, all Light Sussex males and derivatives of that breed I've ever owned had that sort of tail in juvenile males. Won't be a golden rule, but it's been pretty close to it in my experience.
Yes, it's a boy, he has fringe on feathers hens never get fringe on.
Plus he's got one of those triangle feathers showing on his back:

Can you see the internal triangle shape? That's what I drew in the reference pic.
Best wishes.
Yes, it's a boy, he has fringe on feathers hens never get fringe on.
Plus he's got one of those triangle feathers showing on his back:
Can you see the internal triangle shape? That's what I drew in the reference pic.
Best wishes.