Choke chains

RSPCA policy is to recommend owners don’t use choke chains as they’re painful and potentially dangerous to dogs. Some have had neck vertebrae damaged as a result of owners pulling hard on the lead.

A Family has Lost their GSD dog after he’d been left outside (not for long apparently) and the chain caught on something attached to the fencing and choked to death.
Dogs (and cats) collars can get caught on things if not fit properly but there is a higher chance of it happening with a choke chain and they hang loose around the neck when there is nothing attached but if the ring gets caught on something and the dog pulls then they will choke very easily.