I would worm her at least. It won’t hurt the others if you want to worm them. Valbazen is in a few feed stores, but more available online. SafeGuard is in most feed stores and TSC. Look her over for any possible mites or lice as well. What do her poops look like? Oyster shell works for calcium...
How is her crop feeling? Is it empty and flat, full, firm, doughy, or puffy squishy? Can you chipeck it first thing in ammbefore she eats or drinks to see if it has emptied? Does she have access to poultry grit? If you haven’t wormed her recently, use Valbazen 1/4 ml orally, and repeat it in 10...
She may have a respiratory infection such as MG or infectious bronchitis. MG can cause bubbly eye, conjunctivitis, sneezing, and head shaking to clear mucus from the airways. You can flush her eyes with saline or eye wash and put a small dab of either Terramycin eye ointment from the feed store...