If it's your barn you could do what I did.
Found cheap shelves at IKEA and hung them.
My "grooming boxes" are actually baskets I found on sale that fit on the shelves and hold all the brushes, etc I need to groom.
*friend of bar.ka*RIP all my lovely boys, gone too soon: Steppin' Out 1988-2004 Hey Vern! 1982-2009 Cash's Bay Threat 1994-2009
A french cleat is the way to go. Zero protruding parts on either box or wall, and quite secure. Well, it would be susceptible to being knocked upwards, such as a horse deciding to rub its head on it, but I can totally picture an easy fix for that.
You can make one from wood, which would look nice, or just buy a picture hanger, available at any of the big box hardware stores.
Try to break down crushing defeats into smaller, more manageable failures. It’s also helpful every now and then to stop, take stock of your situation, and really beat yourself up about it.The Onion