US Customs and Border Protection officers seized nearly 100 illegal rooster blades used for cockfighting at the Juarez-Lincoln Bridge in Texas Thursday.

Customs officers searched a truck and found six packages containing 96 rooster blades, according to a Customs and Border Protection news release. The blades, shaped like curved ice picks, are often tied to roosters legs during fights and are so sharp, they've even killed people.

Officials seized the blades and fined the driver $500, according to the release.

The blades are prohibited in the US under a law preventing buying, selling or transporting sharp instruments used in animal fighting ventures, according to Customs and Border Protection. Cockfighting itself is also illegal in the US.

"Cockfighting is an inhumane, age-old practice that is primarily associated to other illegal activities such as gambling and trafficking," said Alberto Flores, director of the Laredo Point of Entry.

Drug cartels have actually used cockfighting operations to distribute illegal drugs in the US, according to the Humane Society.

Cockfighting, when two roosters are forced to fight one another for gambling or entertainment, usually results in the death of one or both birds. The birds are often injected with steroids and adrenaline boosting drugs and kept in isolation before fights, which can result in injuries including punctured lungs, broken bones and pierced eyes, according to the Humane Society.

"CBP aims to prevent these acts of animal cruelty with this seizure, which aides in the protection and welfare of these animals." Flores said.