Why Pigs Have Curly Tails?

When pigs are born they have straight tails and then their tails curl as they get older. There's no bones or anything in there so it's all cartilage like your ear is. Next door to the pigs a coop full of chickens has four eggs that one chicken was sitting on. They sit on their eggs to warm them up so if they were trying to hatch these eggs these eggs aren't fertilized because we don't have any roosters. But if they were fertilized the hen would sit on the eggs for about 21 days to keep them warm and then the chicks would hatch out of the eggs.