Wayne, my guess would be that if you had them spayed, they would natually become less territorial but I doubt if they will give up the behavior entirely. Altering cats most definately calms them down and I would highly recommend it. Sometimes Vets give a discount rate. My concern and reason for spaying etc. is to reduce the excess numbers of cats in this world. My two, in this situation are brother and sister so I was in a bit of a worried state as they matured, hoping I would get them fixed just in time. I did. At six months of age.

I would vote to have them spayed, for sure. It is much easier on their health too.

Good luck,

SAS and her brats