I guess they're puppies, but there's a reason you make certain certain large breeds are well-trained before keeping them around physically-small children, I do believe...? >_>; This is not my area of expertise, mind.
...To be fair the thing that actually went definitively wrong here was the leash snapping; it's totally possible reasonable safety was going to be followed. And judging the pups when they're unexpectedly presented with a small animal to chase, is unfair of me.