Sounds like a good plan. Do you use leg bands and records to keep track of matings? In this case I would recommend particularly marking the birds from each line with a different color, and track the matings you make to make sure that you can follow back to the original pairings, in case you get any more inverts crop up on you. I'd hate for you to have to fight that, but it is possible the stock you already had are hiding some dirty secrets. Probably the easiest thing to do, would be to test mate the birds you already had together to see if they are carrying, but not expressing.
Yes, i plan on test mating the birds i hatched out to see what i get out of them. I hope i get good combs
