I think you are massively confusing domestic breeds vs. wild species. That's the problem associating them with poultry, you get responses like this. You never see this confusion with other facets of aviculture or science. I can't figure out why it's such a hard concept to grasp on this forum. I tested my son one day by asking "what breed of hawk is that?", he jumped my case saying "THERE ARE NO BREEDS OF HAWKS!!! THE SPECIES IS A RED-TAILED,DAD!!!" - he was right. Using the Red-tailed as an example as there are multiple color moprhs all over the US, and NONE are considered breeds. No difference between the Red-tailed Hawk and Reeves' Pheasant - except this is a "chicken forum" and that confuses too many.
Dan
Breeds or subspecies breed much more easily than separate species. Wild finches will hybrid easily because they are subspecies.
Same with the peacocks I mentioed. The hybrids aren't pets, mbut mixes bto help stabilize a population of wild birds. The practice is done wth lemurs as well, which are in no way domesticated.
Again, one person breeding a yrid won't cause a lonely George and its often nessecary and creative in strengthening the gene pool and creating new attributes, just as the examples I already gave showed in addition to the lemurs, finches, and many types of poultry developed in recent centuries that have made urban farming so much easier.
This is also a bacis aspect of agriculture as most commerical wheat, tobacco, and some fruits are hybids intentioanlly and have been for centuries. That's not getting into the modified crops--both genetically in a lab or over decades of using natural selection to our advantage--which most crops are. Compare the generic clone bananas that were created by humans to wild ones.