In short: It is very important to remember that cats are obligate carnivores that have no dietary need for carbohydrates. When choosing a diet for your cats it is absolutely critical that it be high in very high quality protein. In 2019 we transitioned to a raw diet for our cats, and have seen excellent results so far with coat, appetite, and GI health - bonus: poops are less stinky! (When you have seven cats running around, that matters!) Some reading material here: UC Davis research; and CatInfo.org - one vet's take For kibble recommend only grain free foods, and ones with a minimum of 30% crude protein. Some brands we like: Taste of the Wild Rocky Mountain Blend, Wellness Core
I feed our cats and kittens mostly raw, with some kibble. Kittens are weaned exclusively on raw food, to give them the best start possible. Info on raw food, for a start, here. Basic info on feline foodhere. I do leave dry food out for them so they can graze if they want, and I make sure to use dry food that is minimally 30% crude protein. I always use a combination of dry food brands, so the transition to their new home will be as seamless as possible. There are lots of good options! Organix, Blue Buffalo, Fromm, Taste of the Wild, etc. I rotate the primary protein source regularly to prevent food allergies developing although everyone prefers poultry. Beef, venison, and fish are generally not desirable for our crowd, not sure why!
For the raw food, I order from two places, although your pet stores will also sell raw food in a small freezer section. I don't like that stuff as much, since it's more expensive and we're feeding a whole herd here! I go between Raw Paws and Hare Today, depending on sales. There's a great Facebook group about raw food: Cats Completely Raw And Proud (Cat CRAP), which you can join if you want to learn more.
Please keep in mind that cats must eat bone and organ meats in addition to muscle meat. So unfortunately just regular old ground turkey from the grocery store isn't a good longterm option. I have recently been buying thighs or chicken necks and hacking them up with a cleaver (it's very satisfying after a long day of toddlers yelling at me!), as well as breasts which you can cut into chunks. It is good for their teeth and jaws to eat not only the ground meat, but to have to work on big hunks of meat. You can also often find very cheap packs of chicken organs at your grocery store. You can separate them into little ziplock bags and get them out as needed! Or freeze separately in ice cube trays and transfer to a larger back for easy separation when you want.
I wouldn't bother with the beef or venison. Only the least discriminating cats will eat it. They love duck and rabbit! It's a little pricier so I don't buy it for my crowd since we go through 5-10 pounds of raw meat a day (that's not including the dry we also supplement with!) If you know or want to look into someone locally who sells meat rabbits, and feel adventurous (and not too squeamish!) you may be able to get some for cheaper that way! Or maybe you have friends who hunt turkey (without the pellets)! There are SO many ways to make this a fun research and exploratory venture!
Water: Fresh, clean water is absolutely critical to your cats overall health. We recommend using a filtered water fountain for your cat to encourage drinking. If that is not possible, then it is best to use ceramic bowls because they are easy to clean and very appealing to the cats. We use this fountain, but there are many others. (Reminder: don't use plastic - it gives cats acne. See below.)
Dishes: Use glass, ceramic or stainless steel, low sided bowls and clean them daily. I've had good success finding reasonably priced ceramic bowls in the pet section of TJMaxx. Plastic collects bacteria from the oils in the cat food and can lead to chin acne, bacterial infections etc. Maine Coons enjoy playing with their food and sometimes their water. We recommend using heavy water bowls and putting trays under the water bowls to prevent floods. Keep the food bowl at least 12 inches from the water bowl. Do not keep the litter pan anywhere near the food and water containers - no one likes to eat by the toilet. Eww.