Wondering out loud.

I have started many hounds by themselves that have opened on track without ever having been shown by an older dog. Its in their blood, and what they were bred to do. But doesn't mean they all will.
Same as curs being silent. Starting a pup of any breed too young, alot of times will cause them to babble out of frustration and/or excitement because they cant keep up with the big dogs. Some grow out of it some dont.
Alot of it depends on the individual dog. I have seen a couple open mouthed dogs "learn" to run silent too.
good luck with your pups