Palm Beach County authorities and rescue group Animal Recovery Mission (ARM) collaborated to bring down three illegal slaughterhouses this week in Loxahatchee, Fla.

Months of undercover investigations, in what authorities have called "the largest tactical strike on extreme animal cruelty operation in U.S. history," according to the Dodo, led authorities to over 1,000 animals rescued thus far.

Authorities have called the raid "the largest tactical strike on extreme animal cruelty operation in U.S. history."

"The animals on this property lived in deplorable structures and improper shelter. ARM investigators had never seen these animals fed or having food nor provided with clean water. The only food source they have available are intestines, blood and carcasses of the newly slaughtered animals. Pigs have been documented by ARM to be eating off the carcasses of hanging butchered animals, swarmed with flies and awaiting customer sales," reported ARM.

A puppy mill was also on site, with the young dogs treated equally as alarming as the animals raised for slaughter.

Rancho Garcia owner, Jorge Garcia, butchered several different animals for human consumption, including horses. Other live animals were used for black magic and also for fighting operations.

Animals killed for slaughter were subjected to sickeningly cruel methods of death: either being shot with a low-caliber gun or stabbed with soiled, dull knife, in what authorities called "hell on earth."

Conditions at G.A. Paso and Medina Farms, the other two illegal slaughterhouses shut down in the raid, were equally as sickening. Undercover investigators were horrified to witness such acts of cruelty of animals being boiled alive or skinned alive.

Among the six men arrested on a multitude of federal felony charges were Garcia, Edgar Bica Sr. and Edgar Bica Jr.

"Horses were being bought from the show horse communities throughout Wellington, from thoroughbred racetracks, from auctions, from Craigslist," ARM's President Richard Couto said of the horses being butchered for their meat, according to WPTV.

Other animals seized include goats, pigs, cattle, along with numerous species of birds, dogs, cats and fighting roosters, Lee County Sheriff's officials said.

Rescue efforts of the remaining live animals is ongoing with 750 transported to safety so far.