The word "irresponsible" means not taking or fulfilling responsibilities, neglectful of duty, failing to meet obligations, unreliable, and careless. Full definition
All this is happening because of irresponsible owners who care more about what they want than what is lawful or ethical. (poochprofessor.com)
The majority of them are offspring of irresponsible owners who did not fix their family cat. (kittybungalow.org)
It's not unusual for irresponsible breeders and puppy mills to try to cash in on the popularity of a breed and start producing puppies without regard for health and temperament problems. (dogtime.com)