That’s just from what I’ve read on genetics that I’ve picked up, I honestly have no idea where I first read it.
But, this website has a brief paragraph on types of dominance. I’m sure there are more, but this was the first one I found. Just the diagrams under the complete and incomplete dominance shows the general idea.
https://opengenetics.pressbooks.tru.ca/chapter/complete-dominance-and-recessive/
I agree that this is much more concerning. I went back to the post above and this is where it was mentioned. I must have missed that the first time I read through it.

Any combos that were not used were culled from the collection.
I’m hoping that it was just misuse of the word cull and they were sold or at least used as food, but culling an animal just because you don’t have a use for it and you don’t want to pay to house/feed is extremely unethical.