Welcome to BYC. It looks like it is suffering from wry neck (torticolis) a condition caused by vitamin E or B1 thiamine deficiency or a head injury. Polish chickens can attract pecking of head feathers, and that can lead to head injury. Treatment can be treating with human vitamin E 400 IU soft gels, human super b complex 1/4 tablet daily, and giving a small amount of cooked egg yolk daily. You may need to hand feed the chicken some watery egg mushy wet chicken feed, 2-3 times a day if she cannot eat.