Using a blue split for self blue isn't ideal but if that's all you have then it's doable. As the others have stated you'll always have that split for lavender in some of the flock and at any given time will express. If you cull from the flock all birds with poor feather quality and all blues without lacing you'll tame the Lav but never get rid of it.
Personally I don't get the interest in lavender. Sure you have a color that breeds true but it lacks luster. No lacing and all the flock looks drab grey. To throw salt in that wound these birds tend to poor feather quality.
Personally I don't get the interest in lavender. Sure you have a color that breeds true but it lacks luster. No lacing and all the flock looks drab grey. To throw salt in that wound these birds tend to poor feather quality.