It took firefighters about four hours to extinguish the blaze that began around midnight, resulting in the death of 34 small dogs of various breeds, a fire station official at Hokkaido's Chitose city told AFP.
Around 70 to 80 canines, including dachshunds and poodles, were being kept at the facility, according to the official and local media.
While the cause remains unknown, the breeder told investigators she "added some wood" to a kennel stove Tuesday night, local broadcaster Hokkaido Cultural Broadcasting reported.
