Personally I don't think ALL dogs are naturally quiet....some are and some are not. Trace, my first yorkie, did not bark EVER....Ramsey, however, barks at everything...a stranger, a noise, an item somewhere that she's never seen in that place before, a bug, her toys, anything.. I should say she is barking at
something she doesn't bark to bark..sometimes you just have to figure out what it is she's barking at...and being alone is on the list too. I leave her in the other end of the house....she barks until she is hoarse and coughs....went and got her...she is sleeping like a lamb at my feet.

Btw, this morning she was barking in the kitchen....a DEAD bug was on the floor...she's barking at a DEAD bug

But I understand...he wasn't supposed to be
there
Friend has beagles....beagles are NOT naturally quiet....they bark all day and all night.