Cats come into our lives in all kinds of silly and unexpected ways, we think that every cat owner comes to understand that. They can find you anywhere and at any time, and you will never be prepared for the day that a cat will choose you. Except that they don't always choose us. Sometimes, cats choose our dogs, and we are just very lucky bystanders.
Seriously, at this point, we're kind of shocked by the number of times we have seen dogs adopt cats before we do. It's like we are not even a factor. If our dog adopts a kitten, then we don't really have a choice but to bring it in. And be happy about it. We don't have a choice about that. We are going to be happy about it whether we expect it or not. And that's pretty much what happened here. It's not the humans who found this pile of kittens, it was the dogs, and after that… well, the humans did not have much choice in the matter.