Unfortunately, dogs as severely brachycelaphic as pekes come with breathing problems. That's what the wheezing and snorting noises they make are- their throat is too constricted and their sinuses crammed into too tight of a space. Some of the really bad-off ones need surgery to correct it. It's such a shame, they're lovely dogs, but that head shape isn't a healthy thing to breed for. There's a movement to breed "retromop" pugs, which are pugs that are a bit more functionally shaped, but I haven't seen anything like that for pekes.
What kinds of snakes do you have? It takes a fairly large snake to threaten chickens, let alone small dogs, so unless you have venomous ones it probably isn't a concern. Nonvenomous snakes that aren't large enough to threaten chickens are best left to their own devices, they'll eat pest rodents for you.
