Hi, I have a 2 year old intact male mastiff (truman) a spayed 4 year old mastiff (cloe) and a 12 year old intact male little river (sam).All was well in our world until sometime last month when my boys took a liking to cloe.For some reason they wouldnt leave her alone smelling, licking, following her around...even licking the floor where she'd been laying after she got up.This went on for alomst a week and then our usually gentel calm truman attacked sam.I wasn't sure what to think.He's never displayed that type of behavior before... & there was no warning leading up to the attack....just BAM truman on sam....he did it again about a week later. The first thing I did was make an appointment to have truman neutered but he can't get in until dec3. I'm hoping this will stop the behavior.I've been keeping the boys seperated except for a few hours here & there with truman on a leash.He doesn't show any kind of aggression towards me, my husband, or my kids but it was a very tramatizing event, & i dont trust him around sam unleashed. I started to the nothing in life is free program with truman & it seems to be going well but we never really had any issues with him before.There has to something I can do with them without putting sam at risk.Anybody have any advice????