Try picking a chicken up, holding the feet in one hand (you can feel your hand warming the feet up) and breathing hot air on their comb. My chicks aren’t keen on being picked up, but in the cold spell last year I would do this, and secretly I think they liked it. They’d stop their usual wriggling, and quite often they wouldn’t lower their under-carriage when I went to put them down, in a ‘just a few more seconds’ type of way.
