If he's a good weight, I wouldn't worry about it. Some dogs just don't care about their kibble that much and are motivated by different kinds of foods. Do you mind sharing what brand of kibble it is? Mainly asking because I used to think I was feeding the "good stuff" when my BEAGLE wouldn't finish her breakfast, but it turned out to not live up to it's name. Ever since switching off that food, my dog hasn't turned her nose up to a single meal. Eating on a schedule isn't really necessary for a dog, but it's nice to have peace of mind that your dog has a full tummy when you're out and about hiking.