It makes him look like a canary!
Depending on how it grows out, you can decide whether to breed it or not. I definitely wouldn't use him in your main flock, but if you wanted to play with genetics and see if you can start a whole new variety of canary-beaked quail, that would be cool.
Nothing serious, but it would be a fun project to play with.
Many defects are looked down upon, but if you think about it, many of the coolest birds originated from selective breeding of "defects". I know that seems the case with many other animals, "Wow, this 'random animal-bird,dog, cat" is "random adjective-shorter,darker, taller" than the others and it in many cases inspires breeding projects. Not all work out, but those that do can produce some pretty interesting things.
Just think of the pigeon breeder who first saw his pigeon sieze up and do a back flip? Yeah, he could have culled that bird, but instead he/she decided to run with it and now you have some pretty cool pigeons that do multiple and random tumbles and flips.
-Kim
