My chicks are 5-6 weeks old now, for the last few days we have a New Hampshire red who is acting very odd, he has his head tucked down underneath himself and walks around backwards, it is very strange. He seems to eat and drink and occasionally fly around the brooder area but other wise acts odd. He looks like a headless chicken walking around backwards. Does anyone know what could be the cause of this? All chicks looked and acted healthy until this started, none of the 29 others seem to be effected.