What a great idea!....BUT....you must give the HN's a long trial as the only available, because they are harder to use. Takes time and patience and should not be 'trained' to during extreme temps, many give up before the birds fully acclimate.You could, GASP!, get a couple of cups and a couple of horizontals and the chickens can choose to use the ones they like best. Which might be BOTH! And if that is the case, they will have the "less likely to freeze" horizontals for the colder parts of winter.