Do you have a shed you can put him in for the night, so he's at least out of danger of predation?
Depending on how many hens you have, could you pen him in a separate house with a couple of the gentler hens, then once he's bonded with them, you could try putting them all back together.
Certainly with a young cockerel in with mature hens, they have a period of approval where he has to prove himself a kind and knowledgeable cock or they will bully him and potentially drive him out. The ladies choose! If he's worth his place he will quickly improve his behaviour, curb his appetites (for treading the hens) and start showing them where the tasty morsels are and standing back while his favourite concubine snaps up said tasty morsels. A mature cock leading and caring for his hens (which lets be honest, don't really need him) is a good sight around the farm.