Join Date: Aug 2009
Location: New South Wales, Australia
Yeah it's reasonably normal.
I'm likely to be completely wrong here, but I've only noticed it in particularly tall breeds/horses, generally with Thoroughbred in them. They usually have long legs (in comparision to their necks) so maybe it's sort of like a counterweight, as they have to bend down more, and often stretch out their leg? I know horses do it with raised feed too - but perhaps it's a learned food association? I have no idea - it's kinda funny though.