Feather problems, brittle feathers, "ratty tail"My experience shows it is a bigger problem with large fowl than bantams.
One guy told me several years ago that he has a theory about adding the slow feathering gene to improve feather quality.
I don't have any plans of getting into a project like that to find out.
Some breeders recommended breeding Lavender to splits ONLY, never Lavender to Lavender to avoid the feather problems, brittle feathers, "ratty tail" and the little marks on the hackle feathers of the males. I don't do that either, but I do use black females from time to time to produce "split" pullets that are used to improve the lavenders in many areas. Maybe feather quality is improved also, but not everyone agrees. As mentioned in
another post, I believe selecting for wide feathers would be beneficial.
It's not that you can't breed Lav to Lav, just that some breeders don't recommend it because of feather problems that can go along with the Lavender gene. Unless you experience feather problems breeding Lav to Lav, then I wouldn't worry.
Sherry
This is a common problem in lavender birds. I have seen this in self blue (lav) Old English Games. The ones I raised had a thin, twisted tail and a shoulder patch on the wings that looks like it never quite got through molting. The good news is that it can be bred out. The Old English Game breeders have developed strains that are virtually free of this problem and I have seen a lot of nice self blue D'Anvers without feather problems. I have only seen this trait in males, but of course it is carried by the females too. So you have to track which hens are throwing males with this trait and get rid of them as well as the males with this trait. This trait is pervasive and can't be eliminated by breeding to blacks. The splits can look perfectly normal but produce lav offspring with this trait. If you are not seeing it in your birds now I wouldn't worry about it. Select your lavender males for GREAT tails and watch for birds that don't feather out completely after they molt.
Curtis