Alternative to cooking: start with canned dog food (the not-recalled kind)mixed with the good healthy kibble, or straight up. If/when the dog stops eating that, move to canned cat food - try it, no kidding! Half of our many dogs lost appetite as they became elderly - 13-14-15 years old. Appetite can come and go. Switch flavors, see which the dog prefers - elderly dogs seem to get tired of the same stuff every day, whereas that's not an issue for younger dogs. Try different brands. Our dogs usually liked Alpo, dog & cat, and they have a decent rep. Cooking for the dog's fine, chicken, rice, hamburger as suggested, etc, but we have preferred to use canned dog food if possible. I think as they age, their sense of smell diminishes, so stronger-smelling foods and flavors like fish can be a hit - the Alpo salmon-&-shrimp flavored cat food for instance, and the beef dog food, have been favorites.
One stopped eating unless we fed her the wet food from our hand, and we did this for almost 2 years, til she was 15.
As they age, protein needs aren't as high, and I believe higher protein such as are in the high performance dry foods, are harder on their kidneys, but we tried to keep up the fat content instead to keep the weight on. Sometimes we'd mix in a little vegetable oil, if they'll tolerate that.
This doesn't mean to not ask a vet, but this can also be a normal part of the aging process, and it sounds like your dog must be over 13. I *love* our vet! She tells the truth, is almost always psychically correct in her diagnoses, and steers us away from expensive tests for very old dogs for whom surgeries and interventions are mostly futile but make the vet practices a lotta dough. (When she's out and any other vet in the practice is there, they always recommend these same tests.) The couple of times we had the expensive blood work-ups on old dogs, they didn't tell us anything that was correctible. One thing that does come to mind tho - could your dog have a tooth problem, making it hard to chew the dry food? Worth checking out.
Oh- we've also fed dry cat food to old dogs with success.
And: another technique that worked for some dogs, some of the time: add hot water to the dry dog food, let it sit for a bit before serving.
I realize none of my suggestions are recipes for home-cooking, but I believe we have added a couple of years to many of our dogs' lives this way. Many mushers do cook for their dogs! Anecdotally though, I knew an excellent and dedicated musher who was cooking for his kennel of sleddogs, thinking he was improving on manufactured dogfood, and had some nutrient out of whack, and his dogs got in big health trouble. So if you're cooking for your dog fulltime, pay attention to the recommended percentages of protein, fat and carbs. (Many of the manu dogfoods are suspect in their percentages anyway since some of their contents aren't digestible by dogs - this includes expensive foods like Science Diet.)
She'd even do salad as long as it was "dressed".
