I have four pens containing late season hatch chickens. They represent six broods with 3 broods in one of the pens (Pen 3). All pens are above ground and subjected to a lot of wind when it is out of the west or east. Youngest brood (Pen 4) still with hen hatched late December 31 to early November 1. Second youngest brood (Pen 2) hatched mid-October, combined broods are early October with two siblings hatched mid September. Balance are August hatch (Pen 1). Largest brood is represented 10 juveniles in Pen 1 and they are already roosting up. Smallest brood is represented by five chicks under hen in Pen 4. As temperature dropped into the 20's overnight with highs in the 40's, feed intake has increased markedly and water freezes over night. With the exception of those under hen, all the little guys are fluffed up much of the day, especially in early morning hours. As sun shines into pens all are moving to sun themselves. Even those with hen do same. Currently all walk on hardware cloth. Soon each pen will be lined with wheat straw and early next when alfalfa hay will be added as well to provide locations that do not conduct heat away from chicks and may collect heat from sun better (darker alfalfa hay). Keeping them watered is going to a challenge. Keeping watereres topped off and in sun, possibly over something black will slow freezing at night and speed thawing when exposed to sun. Oats are being soaked and will be applied in container separate from feeder. I may explore using shaved ice as adults take it well. Protecting sleeping locations for those still in down will be next issue. They chew through a lot of feed to stay warm at night and they can eat only so much.