The thing I've noticed is that it is also learned behavior... Monkey see monkey do. Same with wood chewing. My big one started with it bc when I was only feeding my mini alfalfa and he didn't get any he would stand by the stall divider and paw all night. To the point of the front of his legs BLEEDING because of a ledge on the bottom of the divider. The day after I fixed the ledge so he couldn't Hirt himself anymore he came up to me in the morning both legs cut and bleeding from obviously pawing somewhere again at that specific height and I can't for the life of it figure out where he's doing this now! I have to either put sport boots or at least fly boots on him overnight so he's not injured in the morning. The alfalfa issue is no more as they both only get some at feeding time now.
The mini paws the same as yours, when bored, impatient and when wanting attention. She "built" herself a bed in her stall by pawing in the center of the stall (base is packed down crusher fines) so now she has this bowl shaped bed and sure enough that's where she sleeps every night with the bedding built up around her. Makes for an excellent human trap too when not paying attention... Ugh.
The mini paws the same as yours, when bored, impatient and when wanting attention. She "built" herself a bed in her stall by pawing in the center of the stall (base is packed down crusher fines) so now she has this bowl shaped bed and sure enough that's where she sleeps every night with the bedding built up around her. Makes for an excellent human trap too when not paying attention... Ugh.