A lawsuit filed by Mexican chicken breeders against pharmaceutical companies Pfizer and Zoetis for producing faulty chicken vaccines will be litigated in Pennsylvania, a federal judge has ruled.

U.S. District Judge Wendy Beetlestone of the Eastern District of Pennsylvania denied Zoetis’ motion, joined by Pfizer, to move the case to Mexico, where plaintiffs Incubadora Mexicana and Incubadoras Rancho Grande are based.