Hi Mary, We have found that some chickens take to it right away and some take longer to figure it out. Can you try flicking the stainless steel pin so water drips into the cup and see if they will start drinking out of it. If you can get them to just peck at the nipple it shouldn't take long for them to figure it out.
Feel free to give me a call on my cell at 910-233-0502 to discuss. Thanks, Tom