PORTLAND, Maine (AP) — Postal workers who recall packages and letters piled up in distribution hubs a year ago are gearing up for another holiday crush. The Postal Service and private shippers UPS and FedEx are bolstering their hiring by bringing in about 230,000 seasonal workers to ensure they don’t become overwhelmed by packages again. But low product inventories and port and supply chain disruptions are creating new uncertainty about getting gifts delivered on time. Despite that, U.S. Postmaster General Louis DeJoy said this month: “We are ready.”