To my limited knowledge; most of which is gleamed from living with a cat for longer than I care to remember, a cat will hunt for small animals such as birds, moles, voles, shrews, mice and rabbits. They will catch fish too, if they are near a water source and insects; ours used to love spiders. Not sure if it would catch and kill a chicken; it would certainly take a chick.
Then it will supplement the diet with grasses.
The thing to remember though is that a cat will hunt RAW meat and in eating the skin, bones, feathers, ligaments and fur, it gets a wide variety of vitamins and minerals, carbohydrates and amino acids. We take all that stuff off and COOk the meat, so I don’t believe that even that will be balanced.
I give our cat a high raw diet as much as possible. Called the BARF diet. that’s hard this time of year when stuff goes off so quickly.
When she was younger she would hunt, but she is incapable of doing that any more (don’t tell her I said that
) Sh’es 16, so has hung up her hunting hat. So I just try and give her what I can and I’ll supplement it with a little oil if her coat looks dry; such as olive oil. not natural for her, but it seems to do the trick.
Put it this way; a cat would not eat a high carbohydrate diet naturally with 4% meat; which is what most commercial cat foods consist of 