I like Chris and Keri's automatic chicken door solution for several reasons. The design is simple, solid, and cheap to do for under 20 bucks, and they have detailed pictures with videos, and a wiring schematic to make the process easy for someone who might want to follow in this direction.

I've been looking at several different versions of these automatic doors on the internet and this is one of the first to use limit switches, which might come in handy for future experiments.

This is a plan I would favor because of the low cost and easy to follow directions. Thanks for sharing Chris and Keri.


Edited to add:

After years of research, Mark eventually settled on this automatic chicken door.

You can see a summary of the best chicken door alternatives and why he chose this version here.

If you're planning on automating your coop, don't forget to pick up one of our chicken waterers.  They never spill or fill with poop, and if done right, can only need filling every few days or weeks!