Im sure by now that you know that the chicks should not be on newspaper because it can cause spraddle leg, but sometimes it also happens when they are on paper towels or shaving. In that case, I highly recommend 1/4 inch wire flooring such as you would have with a small animal cage. The poop will fall thru so that she wont get dirty, but more importantly, she may be able to grip the wire floor with her toes to keep from slipping. At first she will need help standing and getting her feet under her, but hopefully she will do better with practice. Make sure that you put her next to the food and water several times a day in case she cant get there on her own.
chel