Goats coming

[Jimr]

Back with another question. I am going to do the slider door as shown above, and I was also going to make three boxes in the back. They will be three sided with open fronts ( in a line across the 12')'4' wide x 4"deep, with a ceiling. My question is how tall do they need to be? 4 feet? Concern is that overall building height is 7ft to 8ft. Do I need to worry about them jumping on top of these boxes and hitting their heads on roof? Or will they watch? Thanks again