In Monticello, FL, down a quiet road lined with pine trees and pastures, Tealbrook Kennels is the life’s work of 86-year-old Barbara Genthner — a devoted breeder, trainer, and Labrador enthusiast.

If your fluffy friend seems to be constantly ravenous, it might come down to their genes. A quarter of all Labrador retriever dogs have a specific genetic mutation that causes them to feel hungry all ...