Farmers most commonly feed pigs soybean or corn meal that has been mixed with dried whey, and they also add some vitamins and minerals, such as limestone and dicalcium phosphate to the food. Pigs can eat both plant and animal products, and they also need to drink water. Farmers ultimately plan their pigs' diets based on factors like age, size, the temperature outside and the housing method used.
The amount of food given to pregnant pigs is typically limited because feeding too much can make the pigs gain too much weight, and this can affect fetal development. On the other hand, farmers need to feed thin pigs more food to keep them healthy, especially if the temperature is low outside, because this will help maintain their body temperature.