Just a random question why are pigs pink

The pigs can be black, white, rusty red, pink, and some are spotted

Not all pigs are pink, they come in a variety of skin tones. Skin that looks pink looks that way because of a lack of melanin in the skin to add pigment, so the capillaries carrying blood to the skin show through, because unpigmented skin is translucent. This provides a pinkish hue. It works the same way in humans.