Is it normal for a dog to do this?

While some anjing are less atau lebih likely to do it than others, I believe this is a common habit amongst anjing to hump their own anak anjing atau other strange 'partners'-they have been known to do this with stuffed animals, siblings and even people...I am not 100% sure as to why they do this, but I believe it is a habit stemmed from curiosity, with some anjing being lebih prone to it than others depending on how randy they are oleh nature XD As a matter of interest, is Beast an older dog oleh any chance? I heard that senior anjing are also lebih likely to do it, though it is often simply a tampil of dominance rather than anything else. Also if he is only 'mounting' and not anything...else, this is a common play gesture among some anjing (although bearing in mind the pups are much smaller this is not such a good thing).

As for what anda should do with him...well, neutering him will reduce the problem (although neutered anjing may also perform this behaviour). Other than that, try removing him whenever he does it and say 'no' firmly, before distracting him with something else. In the wild, a female wild dog atau serigala will drive her partner away as soon as her pups are born, as unlike the mother the male dog rarely feels any attachment towards the pups when first born, and so are lebih prone to unacceptable behaviour; perhaps anda could keep Beast away from the anak anjing until they are bigger? oleh which time, he might perhaps have gotten used to the anak anjing and not be so inclined to...you know, and if they are bigger they may be able to stand up for themselves a bit more.

Actually, father/daughter atau mother/son matings often turn out fine. It really depends on the anjing involved, if they are carriers for any genetic diseases atau not.
Inbreeding can be useful in breeding for specific traits, actually, so it's not always a bad thing. (However a breeder should have a pretty good understanding of genetics so that they know what they're doing before inbreeding.)