So I live in an area where summers are hot and winters can get below 0 at night....I want to make sure my chickens are warm enough! I went out this afternoon and the thermostat read 14 F...My 3 hens i think are getting very cold feet! I have some pine shavings on the floor of their coop, but should I do anything else? They are also shivering some...I want to make them as comfortable as possible help! Thanks!