Many years ago I had a neighbor who skipped out of a rental, left without paying. The landlord, legally, could not enter it for 30 days. they had left the place full of things like fried chicken and junk food, not wrappers, but half eaten food. By the time the month was up, the whole neighborhood had rats. I had a tom cat, Mac, who was a hunter, he was catching and killing rats, I had traps out and was catching and killing them too. I know he got a LOT more than me. When we had killed 25 rats in the house and not dented it, I gave up and called an exterminator. Mac did his best, he was an excellent hunter. We could have used Mr Spot cat to help us.
Find a mom cat who is a mouser, let her have the kittens till they are around 3 months old (or hunting well on their own) and odds are REALLY high they'll all be mousers too. One of the problems with getting cats is everyone wants cute kittens, and they take them too early for them to have learned from their moms (if the mom knows how.) Instinct is important, but so is training. When people raise kittens they don't always raise them to be hunters, it's different skills than playing with toys, so unless a cat has good instincts, learning from another hunting cat is beneficial. It's also a lot personality, some cats like to hunt, some would rather hang out in the sun. Depends on what they find fun.
Getting philosophical this morning, it's kind of like people who homestead. Some will take to it naturally, some will do really well if taught. Some people will never want to do it, if they have to, it will be kicking and screaming all the way. Cats who hunt either come by it naturally, or are taught. And some will just not do it unless they were starving.
My cat lived in an apartment for his first decade, but loves being a farm cat. He isn't the best ratter, but he sure tries hard, and he does get some.
He brings me the first example of each species in case I would like this type. I bop him on the nose with the critter and chuck it back outside, and he doesn't bring another in until he catches something new.
'Theoretically this level of creeping Orwellian dynamics should ramp up our awareness, but what happens instead is that each alert becomes less and less effective because we're incredibly stupid.' - Jerry Holkins
My cat was a championship hunter. She once took down a rabbit bigger than she was, snapped its neck without breaking the skin, and brought it to me so I could roast it for dinner. Mice and voles never stood a chance with her. We even had to be careful which toys we bought her, because the mouse-shaped ones she would rip apart and eat!
When she passed away, the rodent population skyrocketed.
We are Walter's humans. He came to us from an abusive household, so he has some quirks. One of them is obesity, so we've been working on slowly reducing his intake. One year later and I swear he's gained weight! He's either a successful squirrel hunter (I have my doubts), or he's got a side hustle with one of the neighbours and their food dish.