Ok, I got this mare a couple months ago and cannot for the life of me get ahold of her old owner (phone is disconnected). I took her in to a vet and he palpated her, no foal. An old mare I had vet checked negitive also and looked NOTHING like a pregnant horse until we walked out to find a little stud colt at her side so I wonder if this may be the same type deal? These photos arent the best but I got what I could. Her udder is begining to become hard, she has edema going from the udder all the way to her front legs which has gradually came about the last 3 days give or take, she is also loose in her back end and getting longer in her vagina. There was absolutely no resistance when I was moving her tail around at feeding time which is very much unusual for her. She has a SMALL belly to her that you can't see in the pictures, Her sides don't stick out unless she is standing just right. She is also going in and out of "dont touch me" and loner modes when she is normally a very very lovey in your pocket type mare. The vet says the bag is caused by nutrients in the grass and that he's been seeing alot of it lately but it shouldnt get much, if any, bigger and her bag has tripled in size since then. I do not hae the cash just yet to get her to another vet but do plan to get an appointment ASAP.