Costco is being sued over allegedly misleading claims about its four-dollar-99-cents rotisserie chickens. A staple of the warehouse chain, the proposed class action lawsuit filed in federal court in California says the chickens are advertised as containing no preservatives. The proposed class action suit says Costco has systematically cheated customers through false advertising. The chickens allegedly contain two preservatives, sodium phosphate and carrageenan, to control pH levels and slow spoilage. Despite filing the lawsuit, the two plaintiffs say they plan to keep buying the chicken. Costco has now removed the “preservative” free signage and labels in stores.