Puppies chewing on plants

I have two 4 month old Chihuahua pups that are now staying outside during the day with the Golden. I think they are chewing on my plants. My ferns are being ripped up and my hostas have many leaves missing or ripped off and laying next to the plant. I thought my newly emerging Hostas were being devoured by slugs/snails, but I saw one of the pups tasting/chewing on them yesterday afternoon, so I think it is a combination. The slug bait is gone in a day, but the dogs lick at it too when I put it down. Does anyone have a solution? Has anyone had any luck with a pepper spray on plants keeping dogs away.