I'm experiencing some aggression issues lately too. I have a 4 month to 5 month kitten unaltered and Bobby who's close to 1 year that hasn't been neutered yet who are brushing with violence. Bobby wants to play but the Cow hates playing with poor Bobby and hisses and growls big time on the other side Boris (2 year old neutered) has begun to show strange behavior like going in front of my dad and pee in his bedroom right to his face, a cat who has always been clean I'm guessing all this is due to having unaltered males at home (since Boris is perfectly healthy) I'm hoping this all goes away as soon as we have a neuter/spay fest (also have a 6 month old tiny female that looks like a little kitten she hasn't been in heat yet but she needs to be fixed soon too. She's petite, she's healthy it's just she's tiny)
Keep us posted to know if that's what's causing trouble at your home.
" How we behave toward cats here below determines our status in heaven."
- Robert A. Heinlein