Breed adopts aren't only for making hybrids, and can be used to set which (or what) species of offspring will appear when breeding two adoptables that aren't the same species. Like this:
I see what you mean though, since you would need to fill out the form for each outcome, which can take a lot of time to do for every species on your site. I hope someone else will be able to help though! I don't know how to work with the breeding code.