Foals and horses

[Miasters]

So recently my sim adopted a foal. Now all is well and good, except that my foal didn't want to gallop about in the small paddock I built, even though the foal is only small. I brushed it off and purchased a second lot to house her. I fenced off the entire lot, right to the edges. Though, she still wouldn't run. I am so confused, why won't she run around in a fenced area? (I am using cc fences. Not sure if that's the problem or not but I doubt that's the issue.) Thanks for the help!