Thank you for this post. I have culled in my litters, often if you watch the dam she will also que to any unfit pups as well, be it out right rejection of one or two pups while fully excepting all others, or just a little less attention on her part to the pup in question. If you wait and watch those pups you will see that they are weaker, or in one case of mine actually had a defect in her digestion, that we found through an exam with my vet. Many people would not want to know about a culls in a litter, but the dam and the remaining pups are always healthier for it. And I feel ok knowing that no future families will have the heartache of dealing with health issues in the future. And the dog will not be in distress or pain. Thank you again for this post, and yes culling does not always have to mean actually ending the pups life, spay, neuter and many other methods are helpful. It's case by case every one is different.