A dead mouse that an eighth-grader found in a bag of potato chips probably chewed its way in after the snack was delivered to the school, a company spokeswoman said Monday.

An pupil at Lewis-Palmer Middle School found the mouse Wednesday after buying the chips in the lunch line. School officials said at the time his claim appeared credible.

The bag and the mouse were sent to Frito Lay headquarters in Plano, Texas, where employees found a "chew hole" in the bag, company spokeswoman Aurora Gonzalez said.

An independent pathologist concluded the mouse had been dead one to three days from when the student found it, Gonzalez said. The bag had been delivered to the school six days earlier, she said.

Donna Wood, a spokeswoman for the school, said its food service is in full compliance with all rules and regulations, she said. She had earlier said the incident didn't appear to be a prank.

The district temporarily pulled all chips from its vending machines and lunch lines but will offer Frito Lay products again April 2, the first day after spring break.

Frito-Lay is a unit of PepsiCo Inc.