One of the important things that we found was an online chip look-up that lets you see if your register is at least active. This company, AKCCAR, is working to add more chip registers to achieve a universal database. There are four registers online through this link, so if you have your little one chipped through any of the four listed at the bottom of their page the phone number of the register should show up. Cookie is with PetTrac which doesn't participate yet, but I know that Genie has his data up to date. Also, if your dog is missing make sure to pay each year to keep the register active or there won't be any way to bring him home if he's finally scanned.
Pet Microchip Lookup - Powered by AAHA
I try to keep at least one candle lit for Cookie.
Richard