I'm trying to get my chickens to use the nipple waterer, they are between 1 and 4 years old. I've had the nipple waterer in the coop for a couple of weeks and it does not look like anyone has used it as I marked the water level. Has anyone tried putting something on the nipple (i.e. food) to show them how to use. I'm afraid of removing my other watering source until they know how to use the nipple.