Is Harriet Pregnant?

Harriet, our brown pony, came with baggage, maybe. (Fancy is the Pinto.) Her previous owner reported that she may have gotten into a little hankie pank in April this year. The foal would be due March, 2012. Harriet will be three years old next spring, a little young to be mom, but then wild horses don't use birth control.  We keep looking at her barrel shape, thinking, is she or isn't she?  Whadaya think? (