Seven puppies died after being stuck in the cargo hold of an American Airlines flight from Tulsa to Chicago.

According to the Baltimore Sun, the puppies were part of a group of 14 dogs being shipped on the plane and were placed in the cargo hold.

The airline says the puppies were loaded onto the plane at 6:30 a.m. Tuesday and then the flight was delayed because of storms in Chicago. When the plane arrived in Chicago a few hours later, baggage handlers asked the dogs be sent to the vet because they looked lethargic.

In fact, the puppies were more than lethargic, five were already dead. Two more died once getting to the vet, American Airlines initially said.

However, a spokeswoman told ABCNews.com later, “It appears now as if they were alive when the plane landed and died at a later point. We won’t know exactly what happened until the investigation is completed.”

The shipper was not identified.

American Airlines says it does not load up animals if the outside temperature rises above 85 degrees. It was 86 degrees at 7 a.m. in Tulsa, according to the National Weather Service.