Coccidiosis could be a problem with her symptoms. She's at the age when most would become tolerant of cocci in the soil, but she is still close. Also, she may be getting ready to start laying, and just acting peculiar. Bantams usually lay later than 5 months, but I have only raised a handful of them. She may be cold from wanting to lie in the sun. I would be tempted to give her a round of Corid in her water, but if you decide to wait, I would then give her vitamins and electrolytes in her water, then later consider worming her. Check her skin for any evidence of lice or mites.
Edited by rustytb2001 - 11/24/15 at 6:45pm