Rabbits were kept in such squalid conditions that most had to be put down after being rescued by the RSPCA.
The man who had the 18 animals in a garden shed has been warned he could be sent to prison.
Cantebrury magistrates were told that most of the animals owned by 63-year-old David Tutt were suffering from a variety of conditions, including skin and eye infections.
They were found at his home in Mickleburgh Avenue, Herne Bay, during an RSPCA inspection last September.
But the court also heard that he had been issued with a formal warning by the charity following a visit the previous year.
Tutt admitted 11 offences of causing the rabbits unecessary suffering by neglecting them and failing to get veterinary care.
He also pleaded guilty to keeping 18 rabbits in unsuitable conditions.
Andrew Clarke, prosecuting for the RSPCA, said the charges were brought under the new provisions of the Animal Welfare Act.
He said: “The RSPCA first became concerned about the conditions the rabbits were being kept in November, 2006, when an inspector attended. Mr Tutt was issued with a warning and signed an agreement agreeing to improve their living conditions.
“The inspector returned in early in 2007 but Mr Tutt was verbally abusive and refused her entry.”
He added: “A vet who attended in September found there was poor air quality in the shed and no evidence the rabbits, which were kept in hutches, had access to fresh air.
“As a result of their condition, most of them had to be put down.”
Mr Clarke said that when interviewed, Tutt said he fed and stroked the rabbits every day and thought their living conditions were “basically sound”.
But he later admitted they were being kept in an unsuitable environment and he had been discouraged from taking them to a vet because of the cost.
Mr Clarke said the RSPCA would be seeking a court order banning Tutt from owning animals in the future.
David Nelson, defending, called for a probation report before magistrates considered sentence.
The bench agreed but said it should consider custody as an option because of the severity of the case.
The hearing was adjourned until September 3.