OK i placed my waterer a 5gal bucket with 5 nipples on the bottom in my chicken pen last weekend. they don't seem to be using it... i see a few chicks check it out once in awhile. but don't think its being used, i still have 2 of my 1 gal waters in with them. any ideas on how to get them to use them? oh and how high should i have it off the ground?