Flaking beak

[Aime137]

I have two 4 month old cochins that developed a hole on the top of their beaks. Upon closer inspection, the entire beak is wearing away. I have been feeding them Manna Pro starter crumbles and have now added game bird pellets. I thought the Manna Pro starter was good for them until they reached maturity, but maybe not. I don't know if it is nutrition related or if there might be something else that could cause this. Any input?
Thanks for your help!!

 

[ChickaBonBon]

Hello,
This looks like what is going on with some of my chickens. Did you ever figure out the issue. Was your chicken ok? Thanks!