Urethral obstructions are most often seen in male cats and are life-threatening. A blocked urethra can cause death in a matter of days.
Unlike other species, cats don’t have much of a thirst drive and are designed to get the moisture they need from their food. Dry cat food provides only about one-tenth the amount of moisture cats receive from prey animals, living foods, and even commercial canned diets.
The vast majority of kitties fed dry food diets live in a state of chronic mild dehydration. This puts significant stress on the kidneys and bladder, which contributes to the development of FLUTD and urethral obstruction.
I would choose a food high in moisture, high in protein, moderate in fat, and low in carbohydrates. In addition to overall better nutrition avoid dry food especially for male cats because of urethral obstructions. Freeze-dried raw is great and it does not require refrigeration. Just keep the bag sealed with the zip closure. Simply rehydrate and serve.
Cats are obligate carnivores and are metabolically designed to consume diets with the following general composition:
1) animal (not plant)-based protein (>50% calories)
2) moderate fat (~20-40% calories)
3) very low carbohydrate (1-2% calories)
4) water-rich (~70%)
“there is a controlled study of growth in kittens fed a homemade raw diet, commercial raw diet, and commercial heat-processed diet that showed decreased stool volume and improved fecal consistency, better overall weight and body composition gain, and no adverse effects including infections in kittens fed the raw chicken homemade diet.” Joe Bartges, DVM, PhD, DACVIM, DACVN Cornell University Veterinary Specialists, Stamford, CT, USA
For cats addicted to dry foods Vital Essentials has raw Freeze-Dried Mini Nibs that are complete and balanced meals providing high protein, low carbs that has the crunch some cats prefer.
There are many options for raw freeze-dried foods that can be rehydrated to provide cats a high moisture balanced diet.
Here is a great resource: Lisa A. Pierson, DVM CatInfo.org