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 six cats running around, that matters!) Some reading material here: UC Davis research; and CatInfo.org - one vet's take
For kibble recommend only high protein foods, with a minimum of 30% crude protein. We current feed all kittens and mother cats Royal Canin kitten food. Exclusively raw would be best! But this kibble is a good supplement, and helps to keep weight on our breeding females.
Recently, we have learned some concerning things about grain free cat food. We also no longer feed any fish, ever. The best diet is exclusively carnivore - no starch, grains, vegetables, legumes, etc. However, since that is not always possible, a high quality food is an excellent substitute. For pet homes with adult male cats: we are now recommending you feed at least 50% a "urinary diet." Neutered male cats are particularly prone to urinary problems, and the urinary diets help to balance minerals etc to keep their bladders and kidney happy! This is what we have recently switched to for our male cats.
Our kittens are weaned on raw food, to give them the best start possible. Info on raw food, for a start, here. Basic info on feline food here.
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.
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 per 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.