Is that food just dry kibble?
I am not a fan of an exclusive dry kibble diet for dogs. And even when kibble is okay (to give with other food) it should be the topmost 5-star holistic food you can possibly get.
It could be there aren't enough nutrients in that food. Forget the happy picture on the pack or the advertising jargon, or the "Country Home style chicken and rice dinner" label (which is designed to make OUR mouths water, but is basically just ad. hype.)
Look at the ingredients list....
Is there stuff in there you wouldn't dream of feeding to a dog twice a day?...."Animal derivatives" (I mean....what the HECK is that??)....corn....beet pulp....etc
And what actual percentage is real healthy-sounding meat? They can call a food "beef and rice" if it has the tiniest percentage of beef added. But you will find unnamable ingredients listed like "fats of animal origin" (? That just sounds horrendous and from what I know definitely is.) "Proteins of pork and poultry origin"....etc.
Home cooked meat and fish with a small percentage of vegetables added, plus some really good quality well-researched doggy kibble ....not too bad. But you would also need to add a daily supplement perhaps, to that food.
There are those who swear by a raw diet. That is up to you. What put me off that was all the bone involved. My own dog would have choked to death if I'd given her a raw chicken wing, for example. I knew what she was like and that's why I never did it.
But many dogs love that diet and are very healthy on it. Eating like little wolves.