One of my older rid hen has just started acted very strange. She stands in one place for long periods of time and when she does move her gait is awkward. She doesn't stumble but she is very deliberate in each step. She has a dirty butt with a light brownish sYellow pRunny poop. Her comb is still red but seems soft and flops at the back end . She isn't eating much but she is drinking a lot. At night she nests rather than roost. Not sure what to do. Anyone have an idea of what might be wrong with her? Cocidious? Bacterial worms?