Animal behaviorist, dog trainer

For training and walking most dogs, half check collars (material collar joined by a small piece of chain which the lead is attached to) are ideal.

The collar works in the following way:
The material part of the collar is adjusted to the circumference of the dog’s neck so that when the lead pulls on the chain link the collar will tighten to the width of the dog’s neck, but no more. In this way the dog is prevented from backing up and slipping out of the collar, but because the chain link can only contract a short distance, the dog is not choked as with a choke/check chain.

However, half-check collars are training and walking tools and are not ideal for leaving on the dog permanently. Firstly, because the collar fits loosely around the dog’s neck when the lead is not attached, there is the possibility that the collar may slip off the dog’s head and be lost. Of far more concern though, is that because the collar is fairly loose the dog may get it caught on a fence or other object, panic and twist the collar until it strangles itself.

I have also heard several first-hand reports of dogs with half-check collars that have been playing together when one dog’s tooth got caught in the other’s collar, the dog’s both panicked and the dog whose collar was caught started to strangle. In one case the owner actually had to resuscitate her dog as the dog had stopped breathing.

It is always recommended that dogs wear a collar at home so that identification can be attached and the owner can catch or physically restrain the dog in an emergency. However, such a collar should always be a flat clasp or buckle collar that fits snugly, but comfortably around the dog’s neck. In the case of young puppies or active dogs it may be wise to remove any collar when the dog is left alone to prevent the dog hooking the collar on something and injuring itself.