Goats

Goats are climbers by instinct — split hooves with soft grippy pads let them get up anything with a foothold, which is why the yard is built with stumps, ramps, and rocks to keep them busy. They don't actually eat tin cans, but they will taste-test almost anything with their lips before deciding, so keep maps, hats, and sleeves out of reach. Come into the contact yard to brush them; they'll lean into it, and the ones who've had enough will simply walk away.