How does your horse deal with stress?

[Dark Storm]

My lad shows it through his health.. the last time we moved he lost a lot of weight..
Now to look at him, you wouldn't think he was the type to just drop a few pounds over night, but as these two pics show it's happened in the past..

This was him this summer..

This was him two years ago..

Now, at the moment, I think he's lost a bit (his girth is having to go up 2 more holes on both sides), he's eating ok, but I asked them to put him out with the fat club, as I wasn't sure exactly which direction his weight would go in (the grazing is former cow pasture, so rich grass).. he gets 2 nets a day, and at the moment is out at night..
I'll try and get a picture this weekend of his current look, but i'm leaning towards asking them to change his field, so he's getting more grass, whilst he adjusts..

 

[Joyscarer]

Joy never stands still and gets very vocal. She also looks to improve her place in the world and tests your boundaries. She loses her wish to be with you and becomes more self reliant.

She was at her most stressed at the rs she used to be at and was more than 80kg heavier than now despite doing 2.5 hours of work a day because she wasn't on restricted grazing.