It could fix the problem but it is not a guarantee. What you have to work with is a good start. Just because your birds have a few imperfections doesn't mean you are going to have to start over. I have plenty of birds that have imperfections but it is just knowing what those are and when you hatch culling the ones with that flaw. Cull heavy and keep the best you won't regret it! It may take a few generations it may take one it just depends on the genetics and a bit of luck too.I think I'm reading your post correctly. I would hope that a male with a good tail bred to a pullet/hen with a bunny tail would fix the problem, wether or not it takes a couple generations? This trio is all I have to work with as far as Wyandottes. I know they are way better than any hatchery bird but not the greatest. I think it's as good place as any for me to start.