Feeding a stray is a very kind thing to do, but you also need to get it fixed! A cat can get pregnant as young as 6 months old, and she can have two litters per year. By the time she is having the second litter, the females from the first litter are getting pregnant. Six months after that, the females from the second litter, the females from the first litter AND their kittens, and the mother cat are all having more kittens. Get the picture? Plus, those kittens she has must be brought inside and gotten used to people (socialised) BEFORE they are eight months old, or they will be too wild to be pets and you will never be able to find homes for them. Get them all fixed NOW, while there's only three of them! Check a website called Spay USA to find low-cost spay/neutr programs in your area. Or ask your local animal shelter.