We've kept pigs (60 pounds and up) with market wether goats or bucks for many years and we've had no problem, although we do grain the goats up high in a "stilt-like" feeder with a roof. Make sure you check with your feed supplier on ingredients in the different species’ feed being harmful to another when they are kept together. We use a feed mix that is safe for all of our stock. We keep a cow and full-grown pig in the same lot throughout the winter and even though they do not like each other they are both stubborn enough not to move away from one another. I have a photo where one morning several years back, we caught our big black steer laying down with a goat laying on his back and a Duroc gilt curled up by the steer’s belly. I let our two horses in the goat field one spring and it was nearly disastrous. They had been cooped up and needed exercise and took off running. A kid thought my Haflinger was her mother and started running after her. The Haflinger turned around on a dime and not seeing the baby, ran right over top of her and the little one did somersaults. The horses are not in the goat field anymore. At feeding time every critter on the homestead acts like they’re starving and they’re thinking only of number one. The smaller critters need to be able to get into a feeding area where the larger ones can’t, like in a creep feeder. Have a sunny day!