Tamed Horses Disappearing

I've had several horses disappearing from my Minecraft world on PS4 recently . It first happened several months ago (sometime in January I think) but I didn't think too much of it because I thought maybe I accidentally let it loose. However, in the past week, I lost 3 horses! When I logged into my world several days ago after taking a long break, I realized two of my tamed horses disappeared even though they were trapped in a fenced area. I then lost another horse today after my game crashed even though that horse was tied to a fence with a lead. I tried to close Minecraft and then restart my world to see if my horse will come back but unfortunately it didn't. In fact, when I joined my world again, I lost a fourth horse but I was able to find it by going to a place my horse had been earlier. I couldn't find the other three horses I lost though and I'm starting to think they're gone forever. This is an offline world that I only play with my siblings on split-screen mode so I know no one is stealing or killing my horses.