I have an Austrailian Cattle Dog, Jewel. I guess, due to her desert nature, she's not a hole digger, she's a cave digger. She's got a really nice den, under the mobile home, and the chickens, find the surrounding dirt, cool, and one hen likes the den, as a nest.....Just now, I walked around the house to check the hole, and saw the dog sneaking, quickly, out from under the house. You know the body language. I glanced into the den. No egg..As I come back around the house, I see Jewel, covering something up, with her nose. It's her habit to bury things, for later use. I walk over to the spot, and uncover a perfect egg....I wonder how many others are buried, around the yard.