My mare had been quite the loner today, standing away from the herd. She wasnt "due" until March 21 though, so I'm a little concerned. She is a maiden so I do not know how she carries. Her vulva is stretched, her uscles around her tail are somewhat relaxed and squishy, but she doesn't have much udder development. I can get about 4-5 drops, I tried today so I could attempt to test her. Her milk is quite clear, too. She also didn't eat her food tonight and seemed somewhat lethargic and I could see and feel her foal moving a good bit inside. I didn't think she would foal, especially judging by her udder, but I did read that some mares, especially maidens, may not get much until right before or shortly after foaling. Her temperature was 99.7 degrees Fahrenheit. Her vagina was also somewhat darker than my other mare who isn't bred, and her vuvla was about 1 to 2 inches longer than my other mares as well. She has been quite large throughout her pregnancy as well. I will get some pictures and post as soon as I get them.
Use the calculator for number of days in foal. Input the last day your mare was covered and then today's date. If she has reached 320 days, she is in the "safe zone" for foaling. Due dates are a complete guess, most mares foal on time foals anywhere from 320 days to 365 days Steinbeck Country Equine Clinic - Calculators