Why do dogs love to roll around in crap?

I have a golden and a springer that both love to roll in turkey crap. It is their absolute favorite thing to grind into their fur. They also have found some dead critters out by where I live, the rotten fish was especially aromatic. Why is that sort of temptation too much for dogs to resist? Is there something from their hunting past that is ingrained in their canine brains? I live in the country and a couple of days ago they found a turkey crap honey hole somewhere, they have gotten into it both days.