How to keep Bantams off the deck?

[Heliers Chicks]

Can someone suggest a way to stop my Bantams from coming onto our deck and pooping everywhere?

I chose not to clip their wings and they enjoy living mainly in trees on our section, but they seem to like making their way onto our deck and making a mess. Is there anything that I can use (apart from chasing them away) to keep them off the deck?

 

[ChickensAreSweet]

Fencing!

And if that doesn't work, put netting over the fencing (think snow load though).