Stolen dogs are also sold to laboratories for experimental purposes, although I’m told that the labs prefer Beagles.
Dogs stolen for labs *must* be intact dogs.
With male dogs, that’s readily evident.
With females, only a 50-50 chance.
I don’t think that is where these dogs are going.
I would guess because beagles have a fair bit of bodymass, that they can test the results, but with the little legs, they can still fit in those small cages with reasonable comfort.