I'm building a stationary crowding pen and alleyway and I was wondering what width to make that alley and tub exit. Cows, calves, and bulls will be worked in it. The cows have more rib than most do, so I'm wondering if I might need to make the alleyway wider than the suggested 22" at the base of the alley? What about sloped sides, are they worth it, should I have them? Thanks for any help.