Yup you should be able to RFID to do this. Should be able to to put RFID sensor at each nest. Put sensor on each Hen leg. When Hen is in the nest your good to go. Not sure how to handle the variables for that..... to know what chicken... thinking you could just call your box sensors BOX1...
Here is my thought:
1 Raspberry Pi (a small computer the size of a credit card that runs on linux) computer unit (40.00 on eBay), a motor (6.00) and a photo cell (4.00). I think I can code the computer to use the photo cell open and close the coop door by day light. Or can be coded to open...