I have 4 2 1/2 year old hens, brahma, speckled sussex, rhodie and jersey giant. They have all been doing well until the last few days when, in 100 degree heat, the sussex won't leave the nesting box. I have taken her out, and put her in the run twice and she is just eager to get back into the box. When I threw some scratch in with the girls, she showed minimal interest, (the others predictably scarfed it up), her usual loud vocalizing is reduced and when she is disturbed or outside her feathers are uncharacteristically very puffed up. Is this something to worry about? Is there anything I can/should do? thanks in advance for your help.