We have 1 rooster and 12 hens they have started to free range again we keep them in during the winter. One of the chickens that is 2 years old is acting strange. She stays all hunched up close to the ground and her face, comb and waddle are very pale she doesn't seem to be eating. We threw out some scratch feed and she went over and just looked at it then went back under the bush. What do I need to look for or check.