Here we sterilise cats at 6 months. Apparently there are some health risks if it is done too early. Soon the cat laws here are to be changed. Unless you are a registered breeder all cats must be sterilised, microchipped and wearing an ID collar, licensing (we do that with dogs) is also on the cards. Not a bad idea as we all know how irresponsible a lot of people are. Good luck with your little ferals....hope you can get them sorted at a discount price.