I recently read that working dogs should not be neutered until they reach adolescence in order that they fully develop their (herding) instincts. Is this true?
This may be a myth among some trialists but there has never been any evidence to suggest it is true. Some of the best herding Border Collies in the US have been neutered or spayed. Most aren't because they are potential breeding stock but it has nothing to do with their talent. Herding instinct is something the dogs are born with - it is not hormonally controlled. (Some herders may argue for or against neutering with relation to the perceived change in attitude of the dogs - unneutered dogs are often viewed as more powerful/stubborn/etc).