Hole in ducks bill !! :(

[christinagaile]

Help!! My sweet blue drake has a hole in his beak! I noticed it a week ago but it was crusted over so I thought maybe it was healing on its own but I looked today and the picture above is what I found. He is still eating and drinking but I really concerned. Will it heal up and grow on its own? It appears to have a small crack as well I don't know if my dog bit him or if it was from being bullied by another chicks (doubtful) or rubbing against the fence. I never noticed any blood. Any advice is appreciated he means a lot to me.