My three year old golden retriever recently had his annual eye examination and as part of the process had his microchip scanned for the KC papers. Upon searching for the chip, the vet had difficulty finding it, and after some time, found it low down on his right shoulder / leg.
I didn't really think much of it until now, when I am concerned that if the dog ever went missing / was stolen, and was scanned, they would assume he was not chipped and my information would never be found. And I am assuming that he cannot be re-chipped as his current microchip number is on all of his certificates inc his hip and elbow score paperwork!
Has anyone else had any experience of chip migration, and is there anything that could be done?

you could always get him the tattoo id as a fail safe

If you have Petlog premium you can add it to his records & your vet would have added it to his records as well I hope.

It is on his records that the chip has migrated to the leg, but this won't help if he goes missing and someone else scans him as do they scan all of the body?

> It is on his records that the chip has migrated to the leg, but this won't help if he goes missing and someone else scans him as do they scan all of the body?

Yes, they should do.

> Yes, they should do.

Should do, and do-do - two different things, and apart from my concerns about migrating 'chips (which I understand doesn't happen as much as it did originally?), this is what bothers me.   And partly why I held off going any of this much as one of my hounds is now chipped, but not the other - yet.

Well their supposed to but some animals even when it's in the proper place are not picked up due to not being scanned properly.
You could put on a tag the location of his microchip but that can be lost or taken off too.

You can have him rechipped for the purposes of reuniting him if lost. The old chip could be used as ID if he needs any otehr health tests and the new chip would be picked up if he got lost, as both chips are registered to you it wouldn't matter which one the scanner found.

The only minor problem occurs if you were to travel abroad and even then two chips can be added to a passport.

I just did a microchip training course and am a qualified chipper (Barbara/Brainless is too). 

On my training I learnt:  There are many factors which can cause a chip to migrate, and which vets don't know about because they haven't done a microchip specific training.  Some of them are:

- After chipping, the chipper should not rub the area - this will cause the chip to move and it may migrate.  This is the opposite of what happens when a dog is vaccinated, when vets will rub to disperse the vaccine.  Vets automatically rub the chipping sites frequently, leading to chips migrating.
- Chipping should not be carried out whilst the animal is sedated.  Lying down, the skin on the shoulder blades and the pocket where the chip is injected, will be pulled by gravity and the chip is more likely to fall to the bottom of this pocket and end up migrating.  Many vets don't know this and advise owners to combine chipping with surgery.
-  After chipping, owners should be advised by the chipper - for 12-24 hours afterwards - not to use a harness, not to put clothes on their dog, not to vigorously exercise the dog, not to handle or rough play with the dog - all this can lead to migration.  Again, vets don't know this.

The chip needs 12-24hrs to bed in and get attached to the dog inside, and all the above can affect its ability to do that. 

Finally, if a chip has migrated down a leg, it cannot be deactivated from outside the dog.  What is best practice, is that the dog is chipped again between the shoulder blades.  The dog then has 2 chips and both numbers are recorded.  Anyone finding the dog will always scan the shoulder area first, and once finding the 2nd chip will not persist to look for the earlier one.

But you do need to report an "Adverse Event" with the chip, and go through the proper channels to do this.  If you go here, and scroll down to 'Reporting an Adverse Microchipping Event', you'll see that migration is one of them:  http://www.bva.co.uk/News-campaigns-and-policy/Policy/Companion-animals/Microchipping/

You should also contact PetLog, or whatever organisation the dog is registered with, and see what they advise in terms of getting a 2nd chip.

I contacted the BVA about this because my boy's is the same. They said they would keep a note of having two microchips on record, and that it wouldn't be a problem.