There are some songs in the DigiTrad if you browse "Fox" as a title header.

Or could it be The Fox Jumps Over The Parson's Gate? The words are apparently by Randolph Caldicott (died in the 1880's I think). It has a nice bouncy melody.

Video of Peter Bellamy singing it here, but it took the vid a longish time to appear in the box and get itself together (I'm on broadband) so be prepared to wait a bit. Worth it though -

http://video.aol.com/video-detail/peter-bellamy--the-fox-jumps-over-the-parsons-