She told me that she had problems with the chip migrating.
I've been microchipping with Home Again for over 15 years. I've only had one migrated chip reported back to me and that was in a litter 9 years ago.
I just purchased a dog that was chipped with Avid by previous owner's vet as a three-year old just a few months before purchase. When my vet scanned for the EIC test, the Avid chip had migrated from the between shoulder blades to the loose skin at the side of the neck. Vet advised that the chip's location shouldn't cause any problems.
My vet chipped 12 three-week old pups last year for CNM carrier litter testing. As of 7-8 weeks when pups went home, all chips were still in place as I checked them weekly. The female I kept still has the chip at the original implant site at 1 year of age.
Surprisingly to me, the three week old pups seemed less affected by the procedure than the six week old pups.
I normally microchip at 6 weeks.