Two pekins sitting on the same nest

[chardin29]

I have 2 female pekins and one drake. They built a nest under our central air conditioning unit and the two females have been taking turns sitting. This has been going on for 4 days so far. We put some food coloring on one to see if they switched on and off,and sure enough they do. Is this normal and okay? The Drake is very protective over their nest.

 

[Amiga]

My Runners will share a nest. My biggest concern is that they are safe from predators. Sitting ducks are extremely vulnerable. Please protect them.