With food of any sort in your hand and a full food meter, while holding the right mouse button while scrolling over a fence post will do an animation as though you are punching the fence post or putting a lead on it.
It was expected that nothing would happen because of the food meter being full
What actually happened was the "punching" or "tying a lead" animation
Steps to Reproduce:
1. Have a food item in your hand
2. Have a full food meter
3. Hold the right mouse button while scrolled over a fence