[muntjac]

Some of the beak can be trimmed off. Thats the end growth that has no feeling in beaks whether split or not. I'd shape it with nail clippers as best i could. You are obviously not going to get all of that split out. I'd certainly try the super glue treatment, because you obviously need to try and stop the split where it is and grow the beak on past the point where it starts to split.

A bit macarbre I know, but in badly split beaks, I've heard of people super gluing the top beak of a dead chicken onto the damaged beak.
If you have a valuable piece of pottery thats developing a split, a restorer will stop the split getting any worse by bridging the split with wire and this is what you should try and do with your cockerel.

 a false fingernail werks just as well if ya havent got a dead chuck just shape the nail to fit then glue on

[Bodger]

I don't use false finger nails. :oops:  :oops:  :oops:  Eye lashes ? Oooohhhh yes.