While my dad and I were out getting supplies for the run today we were checking out dog/cat doors for ideas for the pop door. One of them had locks and we both wondered if we could use something like what is pictured below? We figured we could add a pulley system to it as well (if necessary) as the door flap is hard, rigid plastic instead of the typical vinyl, flexible flap. Would this be good? http://www.discount-pet-superstore.com/dog_doors/deadbolt_door.htm
I have a doggie door for my pop door. It works great. However, on mine there are strips hanging down, instead of one hard piece of plastic as in your picture. My chickens go right through now. I used to tack them back out of the way, but no longer have to do that.
