Good idea, Bruce, to have vets check for the chip regularly so you know it is functioning.
They are not inserted very deep at all -- just into the loose skin at the top of the neck where they sit in the layer above the muscle but below the skin. It would actually be dangerous to try and insert the chip deeply into that area which is why chipping needs to be done by someone certified to do so. It isn't hard to chip but it needs to be done correctly and by someone who knows what they are doing.
To understand where the chip goes, think about the last turkey or chicken you roasted. You might have skinned it by slipping your fingers right under the skin to pull off the muscle. Or you might (if you were me!) have cut a slit in the skin to insert garlic cloves so they sit on the muscle but under the skin -- you can put them right into a little pocket by pushing them in (a delicious way to roast a chicken BTW!
). That is where a microchip goes, that space under the skin and over the muscle. But you'll also have noticed you can push your finger in under the skin pretty easily. A chip -- depending on the angle, the way the dog moves, and the nature of its fatty tissue -- can start to move around in this area where the skin is fairly loose. Doesn't often happen, or move very far, but it can. The skin is tighter though on the legs and further down the chest so it is unlikely to move very far.
I have tags stating my dogs are chipped less to notify some finder to scan for them -- because the tag that says they are chipped also has my name, address and phone anyway, as is required by Irish law and by most country's laws -- but to fend off dog thieves. Most thieves are looking for intact dogs that can be used for breeding and I hope it will also deter anyone who might ever find one of my dogs and think they'll keep them for breeding, too (almost everyone I meet when I walk the dogs asks if I breed them and if I say no, asks why not!
). That's also why I state 'reward if found' clearly -- because once they are disappointed that they cannot breed, I hope the reward will motivate them to call and return the dog. Don't ever think a neutered male will deter thieves because obviously he is neutered -- I get dogs into rescue now and then where people say of a MALE, "I don't know" when I ask if he is neutered! And even the pound will sex some dogs incorrectly on first glance. So a tag might help those too unschooled to recognise a testicle-less dog.
BTW the Guardian had a big piece on dog theft in Britain on Friday or Sat. I will find the piece and post it. It is becoming a major crime in the UK and in Ireland so PLEASE always watch your dogs, never leave them alone while you pop in the store, or out in the garden without supervision. According to the article small dogs are stolen to order for people who want to buy them, are stolen to use as bait for dog fights
:shock: and to be held for ransom (£2000 recently for one woman's dog).
Chipping is very important and I have a new policy of chipping ALL my rescues from now on -- but prevention, and good clear dog tags, are IMHO far more important.