Thanks for the feedback guys...and to address a couple specifically...
Owned, had I seen any reactions (at all) to the food which she had previously been on for years, I wouldn't be thinking about it. A peanut allergy can be easily fatal especially to a child, so the comparison to me just isn't a relative one. Had she ever coliced before, had trouble breathing, coughed, gotten hives, or ANYTHING else that would have put me on the alert I would not consider it. But she had no reaction save for the bug bites, which both were biopsied and both came back insect allergy so we know what caused those for certain - the insects she's allergic to.
KCC, I thought about it being more systemic and causing them, but we biopsied both of them and both came back as insect bite allergic reactions. Plus even after being off either food allergen for 2 years, she got another lump this year, again from an insect bite reaction. So I'm fairly certain that's exactly what those were from.
Here's another question for the forum though...I've heard allergies can cause labored breathing...I have never noticed it with my mare and she and I Event, Fox Hunt, do Hunter Paces, etc so it's not as if we sit on our duffs
But I have read that labored breathing can cause "heave lines", and when I googled them they look somewhat similar to what my mare has had since I rescued her back in 2008...so anyone familiar with what heave lines look like, can you tell me if the line towards the bottom of her belly here looks like one?
Here's another side view of her...
I can't really tell for sure...and I will say that she was bred twice before I got her, so not sure whether having foals could play a part in how her muscles there look?