There really is a severe lack of feral impregnation stories, on here and other furry sites. By feral impregnation I mean like a quadruped dog who is like a real world dog, impregnating a bipedal anthro canine. Or pick your species. The assumption being, an anthro canid can still get knocked up by a less evolved, non anthro, 'feral' canid.
Dog to dog seems the most fun, and most plausible in the context of an ongoing relationship, sexual or otherwise. And really the only one I can think of even writing stuff like that at the moment is https://thakur.sofurry.com . So, get to it people! I want more feral impregnation!