I am going to make a super simple, lightweight duck tractor this weekend. My two Pekins need to get out more and I can't be stuck to the yard playing "scarehawk" with fear of running inside for a second. What do you think is a good size for two Pekins? I was thinking A-frame, 2 ft high by 4 ft long... Does that sound about right? Do you think they will be able to stand and flap? Or would 3 x 3 A-frame make more sense? I plan on making it light enough for me to carry and it will just be for hour stints, a ducky playpen! Thoughts?