Thank you!! That IS helpful - exactly that thought has gone through my mind more than once. It feels as though something I'm completely unaware of has set him off. I don't know what his life was before he came to the UK, his passport is blank as far as Ireland is concerned - just his birth then nothing until he was over here, 4 years before I bought him. To me, that in itself is suspicious - 8 blank years.@Huggy did you once say he'd had a bad time in his past? I wonder if there's some tiny common factor to these incidents, something so small you maybe don't notice it but that reminds him of a bad incident and so he reacts. Not helpful I know, I'm just thinking out loud, but maybe after an episode try to identify every tiny thing leading up to it. As an example early on Luka would get very tense and shake if I shifted slightly looking over my shoulder for traffic, with what I now know I suspect he was expecting a thrashing - could there be some connection like that in his head?
I used to do that with Storm. If she was looking like she was in coiled spring mode, I'd either lunge her or freeschool. Just something to take the edge off and then I'd feel like I'd done something with her. Sometimes she'd be fine to ride after letting off a bit of steam, others not and I'd just call it a day after lunging.If he was a mare I'd have this sussed
What does he do before he explodes, it might be very quiet and subtle and start at the field, you mention you can guage when it's coming so that does suggest his attitude.
If he's one of those sensitive souls, it could be that your saddle is fine, but irritates on occasion. Might be worth looking at the pad and girth - I speak from experience with another sensitive little soul. Watch him when you tack up.
Is he reaching a point where he says, I am done, I am tired, wan't to go back? How fit is he to do what you are currently doing for example? If it's mid ride, is it the same areas?
Or, has something upset him earlier in the day and he's just letting go of it. I am thinking deer, Badger, other horses.
There are days with mine when I arrive to ride, take one look at her and think nope, let trot that off on the lunge!
When you sense he's going to have one of those rides, do something else, he's still doing something and it may refocus him. It will be interesting if he still explodes when you feel he will and you are not actually on board.
Ger someone out to help you with that.