The door closes automatically when the bird goes into the nest,Do you have to close them every time they go in then open them again?
then you have to keep an eye on things every hour or so to let the bird out after it lays and record what bird laid what egg.
If you have a lot of birds you'd want them to be banded to you can keep usable records.
Read thru this thread.....
https://www.backyardchickens.com/t/567357/the-trap-nesting-thread/160
....maybe you missed it on GOP's last post.

). So the mother hen was just like Millie, but less color and more white (which was her base color). So I guess just breed the colors that you like 