It is suggested to have 1 more box than cats. Sometimes that is not possible but you really do need atleast 2 boxes for 2 cats. Also please don't let them outside. For one thing they are unneutered which means they can add to the uncontrolled reproduction of unaltered outdoor pets. Two, there are soooo many nasty things that can happen to them including diseases such as Felv and FIV 2 big ones not including the dangers of poisening, cars etc. Please the first thing is get your boys neutered. If neuter cost is an issue try one of your local shelters as they sometimes have clinics for spay/neuter and it is much cheaper. Please keep us posted.