Okay this is really a wierd question and I will just ask. Does anyone have any horses that have to "releave" themselves as soon as the first back of shavings hits the ground?

Really we have a horse and EVERY single time we break open the first back of shaving he lets er rip. Instantly..

I just want to make sure this is not some type of Marking behaviour I haven't every heard about and should be in the know.