Hi! To first begin, I have 5 cats, two of which are males and the other three are females. They are around 5 months old currently. Yesterday, I took both male cats to the vet to have them neutered. When I picked them up later in the day and brought them home, they were still very groggy which I'm sure is normal. However, my three other female cats were acting very aggressive towards them. All of these cats are related and have been together since day 1 and have never fought and are very loving with each other. However since the male cats have been neutered, the female cats have been hissing at them and running away from them. Is this normal behavior or should I be concerned? Thanks!