I'm surprised to hear about all these dogs who aren't motivated by food. In 10 or so years of teaching classes, I have only run across two dogs who truly had extremely low food drive. One was a Sammy/Chow mix and the other was a Shar Pei. The Sammy/Chow was free fed and lived with "grandma" who would cook all sorts of things for her every day though, so I suspect her issue was more learned than anything. All of the other dogs who's owners said they "didn't like food" did fine with the right treats and/or some minor adjustments to their environment.
The biggest thing that hurts food drive is free feeding (leaving food out for prolonged periods of time). Free feeding also seems to create poor feeders. Beyond that people sometimes unintentionally encourage dogs to be picky about their rewards by teaching the dog if he holds out you'll keep offering something better and better. In a way this can devalue food as a reward, much the same way as free feeding does.
Certainly dogs all have a lot of difference in their levels of food, toys and
prey drive. But you can always improve on what you have.
Providing the always eats his meal well. The first thing I would do
would be to start using his meals for all of his training instead of feeding him out of a dish. This sort of thing can encourage dogs to value food a lot more by having to work for it. If you sometimes can't use it all for training some days, it's ok to give him a lighter meal from time to time. If you can't use it all most days, give him the last of it in a food puzzle toy so he still has to "work" for it.
Keep sessions very short at first - have him work for 5-10 rewards (1-3 pieces of kibble would equal a reward) at a time but aim for lots of these very quick sessions every day. Sessions like this are very easy to work into any routine.
If the dog doesn't eat his meal well, your first question should be if his food may be making him feel icky. Sometimes dogs who don't eat well are trying to tell us their food doesn't agree with them. Imagine if your meals every day were always the same thing and always gave your bad stomach cramps or even just made you feel general malaise. This sometimes is the case with dogs. I know a dog who was a bad eater his whole life, despite the owner trying multiple different kibbles. He also had some skin, allergy and immune issues (hypothyroid). For 10+ years he ate just what he had to and didn't like treats much either. Then when he was 11, the owner tried feeding him a diet of just green tripe and what a difference! He now is eager about his meals, eats everything and likes treats. He has also improved some healthwise. Likely he had a food intolerance that didn't cause some of the more noticeable issues like loose stool but made him feel poorly. I had a dog myself that was a picky eater, also a dog with allergies until I put him on raw food.
If you don't believe the dog's food isn't agreeing with him, your first step in increasing your dog's food drive (and making your life easier) is to teach your dog to eat. This article outlines what to do pretty well:
TeachEat
Well meaning owners very often teach their dog to be weird about food. The dog doesn't eat a meal or two or doesn't eat well so the owner worries and starts adding "extras" to make the food more appealing. The dog may eat better for a bit then go back to eating poorly again. The owner then adds more stuff and tries to encourage the dog to eat with handfeeding. This starts a bad cycle of the dog holding out for more but worse, it adds a lot of stress to the mealtimes. I have seen dogs who actually became afraid of their bowl because of how much anxiety the
owner would develop around dinner time. No doubt the dog didn't want to eat - the dog didn't even want to be near the kitchen when the dinner time ritual started. There was nothing wrong with the dog, other than having owners who worried a bit too much about why the dog would sometimes choose not to eat all of his dinner. And the dog was able to be "rehabbed" into a normal eater, once the owners were "rehabbed" into acting normal about feeding the dog
