Can a dog sleep under an electric blanket?

Sure a dog can sleep under an electric blanket, however, should the dog lick or chew, it becomes a dangerous blanket. A better plan is to offer fluffy bedding that can be tampped down by your dog. Dogs naturally turn round and round to make their "bed" in tall grasses or dig to create holes for them to burro into. Having a "dog bed" with sides, that is appropriately sized for your dog when curlled will give them additional heat that they need. You can always lay a towel over them, but unless they realize the warmth they get from being under it, they will usually get out from under and lay on-top of it by morning.