My plan is as follows:
Install an RFID reader at the front of each nest box (8). Two going out of the coop into the ourdoor area (so I can tell direction). One around a USB weighing machine (postal scale) next to the feeder so that I can randomly weigh the girls. Two more in the "chunnel" aka chicken tunnel that leads from the outdoor pen into my fenced in orchard.
Each of the RFID readers generates the 2-wire wiegand protocol and these are all sent to an arduino which just sends valid decodes down a serial line (really USB) to some small computer that has network access (this may be a TL-WR703 -- a $22 wifi travel router that you can flash with a linux system).
The RFID readers are based around a module from china and a custom made antenna. The arduino decoder is probably a teensy3. Two RFID readers and one teensy3 can (I think) fit on one 10cmx10cm PCB. Only one of the PCBs has the teensy3 on it, and all the others connect back to the master.
The most expensive bit of the readers is almost the case (which look to be somewhat over $11 each inc shipping).