Change stresses out a chicken and it sounds like she could be in shock. On top of that she is a polish so not only is everything new she has poor vision of what's going around. Everything is scary, new and she can't see a thing! Sitting down might feel like the safest thing for her to do right now until she adjusts. First I would highly recommend trimming up her crest so she can see. It makes a huge difference in a Polish chickens personality when they can see. Next I would treat her like she's in shock. Put her and her sister together somewhere quiet and warm with little environmental stimulation. Adding some electrolytes and vitamins to an extra waterer will help with shock, stress and give her a boost through the transition to a new environment. Wetting their food might also help to make it more appetizing.