Rocky was chipped by his breeder.
She used Avid.
A few years ago I asked my vet to scan Rocky.
His scanner could not read the avid chip.
(just was able to read "avid"
Maybe he has a different scanner now that
is universal.
I think their is a chip called Home Again,
that seems to be a popular chip around here. and
I heard it doesn't move.
I would check with the shelters to see which chips their
scanner reads before deciding on a manufacturer.