The effect of this phrase is that the hunters were trying to hunt down the runaway slaves as if they were animals - four-footed prey that had to be hunted down with guns and dogs. The phrase shows the degrading position the fugitives were in, as well as their masters' cynical, inhumane hatred. The author further explains that the hunters, when they didn't hunt, were in their homes, spending time with their wives and children and saying their prayers. This hypocrisy is especially striking.
