There are currently 5 companies selling microchips for animals and selling scanners. Each scanner will, of course, read that company's chips, and some state that their scanners will also read the chips of other manufacturers. Companion Animal Retrieval System using a microchip which makes use of the Destron chip and scanner. Most companies will donate scanners to local shelters and pounds if they can get the vets in an area to buy their chips. In the U.K., the National Pet Register, which also uses chips, is operated by Wood Green Animal Shelters, which has some affiliation with the Kennel Club.
Insertion is less traumatic than a tattoo.
Being used much more frequently than tattoos, according to some vets. Some scanners do not read chips from other manufacturers. NDR, however, is said to have given their number to all shelters in the United States. It is not necessary for a vet to tattoo the dog, and often dog clubs holding Canine Good Citizen tests or matches will have a tattoo person on hand. Some breeders have obtained the equipment and training and also can do the tattoo.