On the outside looking in, the question is how many breeders have P1 herds?
Hopefully this is an "the emperor wears no clothes" moment & deer farmers now read a bit about Mendel & genetic theory.
It doesn't have to be hard, if you can get some good P1 does you can use any genetically different P1 sires to produce great hybrids, both typical & non typical. Just dont breed from these F1 animals or polute your P1 herd which you need to maintain so as to produce the hybrids. The hard part is finding the P1 does or having the desire ,dedication & determination to produce your own. The rewards are certainly there for those who can. Both in stud P1 animals & terminal but magnificent looking F1 bucks.
At the moment I am running two different herds of P1 Fallow & two different herds of P1 rusa (as well as a few other species). These will never be polluted. I have the choice of putting P1 sambar over both species of rusa, but I don't like doing this as it goes against my own nature. I will also never cross the Persian or Hungarian fallow. I will however establish another herd & line of P1 European fallow deer in a couple of years to produce F1's from with the Hungarians. I will try to have Danish fallow, but I might settle for English park deer instead. This new line of fallow will also be P1 animals & never polluted, I will cross the best from both lines to produce bucks with hybrid vigour, they will be great, but they will all be terminal & never used on my place. This type of model is used by many different animal industries.