Ok, i dont know your location. But I am from North Europe and this year's winter is like spring. Usually we have snow in January and 4 F degrees. But spring flowers are beginning to bloom.
Hi! My opinion is that your birds do not have eye disease. Head shaking is more climate dependent- wind, draught, dampness and so long. I have several experience, bird first get bubbling water to the corner of the eye, especially roosters. If you dont notice it, the eye is swollen already. If...