Puzzling

So my boyfriend Wes came out and rode Milo this evening and did a good job =] Milo packed him around pretty good once Wes showed him that he wasn't just a supplier of cookies.

But on another note, I've had some confusion as to why Milo has been getting stocked up the past few days. He has a stall and paddock and gets out about 5 times a week for a ride or turnout. At first I thought he was stocking up because of not moving around enough. Than I heard sometimes they will stock up if they are too warm, so I've been removing his lightweight blanket during the day and keeping it on at night. So last night and all of today (about 55 degrees today) his blanket was off, but when I arrived tonight to ride he was still stocked in the back. Any ideas as to why this might be happening and what I can do about it?