Dogs, both big and small, are notorious for checking out things with their mouth. They lick them, chew them, and sometimes eat them.
Even when you dog proof your home accidents can still happen. For instance, has your Sheltie recently discovered the art of eating crayons? If your dog ate a crayon call your vet to ask what you should do. You may need to look on the paper of other crayons to figure out if the crayon was non-toxic. Most crayons are. Your vet may also recommend that you keep an eye on your Sheltie’s bowel movements as constipation may occur. If your dog does get constipated and unable to pass the crayon or anything else, call your vet. In most cases, your Sheltie will pass the crayon without any trouble. The only thing you will notice is a color change in your Sheltie’s poop.
Source: My Sheltie Ate a Crayon