I have a Buff Orpington who has been sitting for about 3 weeks. First I would take any egg away from her, she still sat on golf balls. Finally I gave her 2 eggs to sit on. Whenever she would get down to eat if another hen was laying in her nest she would just go to the next nest and sit on any eggs in that one. I would always take away any new eggs and put her back on the 2 I gave her. Then I put about 4 golf balls in with the 2. Those I put in about a week ago. She won't stop sitting and I don't know how to tell if the 2 she is sitting on are good. Any suggestions would be very helpful.
You need to do a search on how to candle, and what you'll see. Then candle them to see if there is development. If there isn't, you can fake her out by switching her 2 eggs for 2 young chicks (as long as they are less than 3 days old she should accept them). Make the switch at night. Maybe post an ad on Craigslist for what you're looking for, since this isn't a great time of year to find day old chicks... Good luck!!