There may be an issue related to beak growth,even mites. I don't see it my homers, but I have in my rehab birds but it is usually the top beak. I have used baby nail clippers and/or a file, you can pretty much see where the new growth ends. They have hard time cleaning and pruning their feathers, also with long beak issue.
Another pigeon will be nice company for Milton, and yes they can bond. If he is a male he will do well with a hen, but then they probably will mate and then you will have eggs and babies too...if you want.