Some slaves (e.g. some farm slaves - but not all) were kept permanently in chains due to being dangerous/unreliable, while others (e.g. indoor domestivc slaves) were not. Presumably these collars were used for the chained slaves who were assumed likely to try to escape, but I wonder how common they were? Being enslaved and chained up would be bad enough, but having one of these chafing around your neck would take it to a whole other level!
Ben
