This can be a serious problem. Border collies (this dog was a border-collie cross) are bred for sheep herding. However an out-of-control dog doing its herding t

This can be a serious problem. Border collies (this dog was a border-collie cross) are bred for sheep herding. However an out-of-control dog doing its herding thang can cause a flock to squeeze so tight for so long that sheep die of stress, heat or exhaustion.