I don't think your mesh is too dense, except in the chest. You can use hooks to go from an area of dense geometry to one that isn't. But I think that yor model is coming out great!
If the bird is going to be able to turn his head at all, you need to add a couple of rings of splines between the shoulders and head, otherwise you are going to have problems.
The beak being a different mesh from the body isn't a problem, you can assign the points to the head bone or to a "beak" bone that is a child bone of the head so that it will inherit the motion of the head.
Version 11 hair does make good feathers, and you can add an image to the hair to give them a more realistic look. There is a thread on the alpha forum that will give you some ideas. or you may wait to do that once V11 becomes the release version sometime next year, if you don't want to risk using pre-release software.