Why use RCD's?

We live and hunt in south Texas. Hogs are notorious for finding thickets of brush that are extremely hard for the dogs to get to. our start dogs have no problem finding hogs but what we consider RCD help them to keep the hog until the pits get there. Becuase of the size and weight it's tougher for a pit to get through the brush rather than a pit/ cur cross that catch well and are strong but not so heavy. We have onehound that doesn't stop until a hog is found so having RCD already on the ground helps to stop the hog until the pits get there. To me it's alot like a help dog except they don't bay as much and catch pretty hard