Inside Out investigated claims by people unhappy at the state of puppies bought from the Ivy Leaf Kennels at Burnhope, County Durham.
Some animals died within days of being collected and others needed veterinary treatment for illness.
We approached owner Kevin Knox who declined to be interviewed about these allegations but did issue a statement:
"In this statement I have attempted to address the concerns raised by the BBC in a letter to me dated 15 February 2010. I feel it inappropriate to be interviewed on camera by the Factual Programmes Unit but it is my wish that the contents of this statement are made public on any programme made by the Unit concerning Ivy Leaf Kennels.
"I have been interested in dogs as a hobby for most of my life and became a registered licensed breeder in approximately 2003 in which year I commenced the business known as Ivy Leaf Kennels. During that time my staff and myself have established a conscientious and caring business with many satisfied customers from whom we have received many referrals.
"Towards the end of 2009 the kennels became infected with a strain of parvo virus, which causes stomach problems and death in puppies. Due to the lengthy incubation period of this virus we were initially unaware that the kennels had been infected and also unaware that some of the puppies sold by us were carrying that virus.
"Unfortunately some of these puppies died shortly after they were delivered to their owners and we at Ivy Leaf Kennels were devastated when we realised that we were the source of that virus.
"Once this fact came to our attention we all worked quickly and conscientiously with the assistance of a veterinary practice to resolve the matter and we are pleased to say that the virus was soon brought under control.
"Many customers who bought infected puppies from us had free Pet Plan Insurance, which was provided to them on the sale of the puppy. Many other customers who bought infected puppies from us had their money returned to them. To my knowledge no one has suffered financial loss as a result of this unfortunate incident.
"Most of the puppies sold by Ivy Lease Kennels have been bred on the premises from parent dogs owned by me. Occasionally I buy in puppies from other licensed breeders around the country. On sale all our dogs are taken to our own vet for a health check and a first vaccination and on receiving their new puppy the owner is always assured of our continuing assistance and support.
"We must emphasise that we do our best in this respect however we accept it is unfortunate that we cannot please everybody all of the time. Even the most successful business has some dissatisfied customers. It is a fact of life. So far as I am aware we have had only one contact with the Durham Trading Standards and this was amicably resolved.
"The virus infection at the kennels had been a terrible and stressful time for my staff and myself. The death of these puppies and the resulting distress to the owners has been a severe body blow to ourselves and our business into which we have put so much time and dedication. We feel we have dealt with our customer complaint in a reasonable and helpful manner.
"We are pleased to say that the virus has now been eradicated and we believe we are now able to continue our business as before. If there are still dissatisfied customers then Ivy Leaf Kennels will be willing to discuss all matters with them."
BBC Inside Out North East & Cumbria