Dogs are only slightly more discerning than goats in their dietary choices.
Things my wife has had to surgically remove from the stomachs of dogs: Linoleum. Charcoal briquettes. Wood. Rocks. Socks. Clocks (well, okay, a wristwatch). A deflated, but otherwise intact, soccer ball.
And, there have been a few things that needed to be removed non-surgically. Those happen on what we might call, "Dog Butt Surprise Day".