I have 4 adult cats and currently 6 kittens who will hopefully be sold shortly as they're at the homewrecking stage now 
I can safely say that feeding cats does not diminish hunting capacity, it just keeps them near to home so they keep the house and buildings rodent free and the garden bunny free rather than straying further afield to get a meal 
My catflap has become just a hole in the door after one cat brought a bunny in at high speed and trashed the flap - finding feathers, back legs of something or a stomach lying on the floor is not great fun but I live with that rather than mice running across the living room carpet and kitchen surfaces which I had before the cats arrived 
i got 4 kittens from a feral cat i have how much you selling yours for?
So sorry I only saw this today, months after the question
I sold the lot no bother at between £35-50 (gingers were dearer and went like hot cakes
) but I checked other ads at the time and apparently £50-60 is the going rate for moggies like mine so that's obviously why..
The neutering campaign has worked so well that there are frequently no kittens to be found in private homes or shelters, and given shelters seem to want "donations" which they set at pretty much the same price as buying, I'm not sure what the difference is except that as a charity they get a lot of free support, pay less or no tax on their income and give people a sense they are doing a good thing by buying from them rather than someone who has had to raise the kittens off their own finances and clean their own carpets
but maybe had a good time doing it
All my girls are now neutered so no more kittens here since January when I got a deal from the local cat rescue to put 3 girls through them for £100 in return for trapping the local feral tom for them which they'd failed to catch in the last 3 years - took me a couple of nights
The one I had done at the vet was £100 just for one which was one of the reasons I didn't get another done until this opportunity came up while chatting to the cat lady
Interestingly a lot of folk don't think they should pay for kittens at all but would pay £500 for what is basically a crossbreed mongrel with a made up designer label name
Breeders of both put masses of effort, time and money in extra feeding for the mums not to mention all the things kittens/puppies need from weaning foods wormers etc, so I reckon it's a throwback to when kittens were commonplace on every farm all year round and folk were glad to give them away.
So the pressure to neuter has in effect made kittens rare enough that the charities that put that pressure on can now make good money from selling the kittens donated to them or birthed by trapped ferals, while calling it an act of charity with a fixed "donation", while all the folk that would have given kittens away now can't afford to if they've paid the costs of breeding them which vets and feed companies/supermarkets have now created to serve THEIR business interests, AND those folk that try and cover a few of the many costs get slagged for not neutering by folk that either work for one of those charities or commercial interests, believe those organisations' marketing campaigns, or are old enough to remember that kittens used to be free
Go figure - the politics and commercial interests win over ordinary folk yet again
whether they breed and pay feed and vet costs or don't and buy their cats from charities and pay the feed and vet costs from that point on
