Police seized 22 dogs in Sheffield, most of them believed to be XL bullies.
The breed was banned in England It is Wales in February, and owners had to apply for an exemption certificate.
Last month, activists received the green light to file a challenge to the High Court against government ban.
South Yorkshire Police say they found the dog breeding facility in Sheffield on Thursday.
Officials say dogsincluding puppies, lived in “terrible conditions” on plots in Infield Lane.
Dog law officers and the RSPCA also attended to support the police.
Six of the dogs had to be put to sleep immediately “to end their suffering”, the force said.
Chief Inspector Emma Cheney said it was against the law to breed XL bullies since the ban came into force.
“In addition to the investigation into these dogs being XL attackers, animal cruelty and suffering will not be tolerated in South Yorkshire,” she said.
“The remaining 16 dogs remain in police kennels while our investigation continues.”
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Police say a suspect has been identified and investigations continue.
The public has been asked to get in touch with any information they may have.
This story originally appeared on News.sky.com read the full story
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