When it happend by us last year I think it was late in January sometime and it was below zero for like over a week and we had alot of snow and ice layers last year and the birds were really conditioned down from itI think by that time in Januarywhen the long cold hit em hard. The farm I do most of my hunting on the birds get the daily hot lunch program so they are usually in pretty good shape. Over all winter last year was tough on the birds in WI as kill numbers were way down from the previous years. We still have great numbers of birds and nothing to complain about but theharvest was down. WCL