And FWIW, I would doubt she is. It's rare for a horse to accidently end up pregnant. Stallions aren't usually roamin' loose in neighborhoods. ;~D
If they had bred her, they could have perhaps marketed her for more money in foal.
Well if it's rare then.....
Something else I noticed today too. She's real firm around her rib cage but at the back where side meets flank she's pouched out. It's soft like fat and more noticable on the right side. It's not tender or feel like a growth but there.