looks like a mix of a harlequin... I'm not expert but cuz of the body feathering. the head is a mystery, maybe a mallard/harlequin mix? idk, just a guess, hope this helps
It's hard to say being it still only has its juvenile feathers...Those will get replaced with adult feathers that will be his true colouring at around 4 months old...I guess a Welsh cross?....Some do not get green heads till after the juvenile molt....