I have 2 golden retrievers, ages 3 and 2 and both of them chew and have at times, eaten small rocks, why are they doing this?

Hi golden mom, have run into this situation before and actually know there is a term for dogs eating/chewing rocks, rather a dangerous past time, it is called 'PICA'. A canine obsessive disorder usually brought on by boredom. It has to be stopped, and you being the pack leader has to initiate;professionals agree this can be done by more playtime, more physical activity.