I'm just torn. I need a black rooster to fit my breeding plan, and I can't get one from the splash. I don't want to bring in any outside blood until I learn what I'm working with. I have several chicks growing out right now, two blues that I'm sure are roosters, but they won't be ready for breeding for 6 more months, then it will be another 6 months at least before I can hopefully grow out a replacement black. I'm fine with waiting that long, but I want my other 4 laying hens producing chicks as well. If I put them with the splash rooster, I will get a ton of splash chicks that sell well, but I don't want to risk over diluting my blues and splash
Use your Splash this year. Keep the best blue cockerel that he produces for next year's breeding. Then pick the best black cockerel that the Blue son produces. It will take more time, but at least you won't be continuing that leakage.