United Airlines recently had to bar a woman from traveling with a very unusual pet – a peacock.

According to The Jet Set, the woman at Newark Liberty International Airport tried to bring her emotional support peacock onto a United Airlines flight. The bird did have its own ticket, but was ultimately denied from boarding.

A spokesperson for United Airlines says that the customers was told in the lobby that she would not be able to travel with the peacock.

“This animal did not meet guidelines for a number of reasons, including its weight and size,” spokeswoman Andrea Hiller said in a statement. “We explained this to the customer on three separate occasions before they arrived at the airport.”

Hiller says that United Airlines is dedicated to working with passengers who need an emotional support animal to get them through their flight. Customers are required to provide documentation from a medical professional. They must also give 48 hours advanced notice.

The U.S. Department of Transportation says airlines are not required to transport certain animals like snakes, ferrets and rodents because they could pose a threat to the aircraft cabin. Other unusual service animals like miniature horses, pigs and monkeys are evaluated on a case-by-case basis.