Thomas Hutton and his partner Bronia MacMillan have trained spaniel Beau since he was rescued from the property in June 2019 as part of an investigation led by Mr Hutton.
Beau was living in filth and squalor with a large number of other dogs, and many - including six puppies - had no bedding, food or water.
The 35 animals were living in makeshift kennels in rubbish-filled barns and many were standing in their own faeces.
They were taken into RSPCA care and treated for a range of bacterial conditions and malnutrition. Many were not properly socialised and needed behavioural classes before they could be rehomed.
Mr Hutton was so taken with Beau that he offered to adopt him and he now lives with the couple's two other dogs, Arrow and Newo.
He said: “I had two spaniels as pets anyway and Beau seemed such a nice character we decided to take him on. He immediately made a great addition to the house.
“He was in a poor state when we rescued him but he has come on leaps and bounds and as he enjoyed agility classes my partner decided to enter him in a competition.
“Last month we took him to his first contest in Staffordshire - as they had not been able to take place due to Covid restrictions - and not only did he come first in one competition but he also came second and third in two others.
“We are so proud of him and how far he has come. Beau is a completely different dog to the one I rescued when he was frightened and shy and in poor health.
“It didn’t take him long to come out of his shell and it is so rewarding to see him loving life and doing so well.”
The original owner of the neglected dogs was given a suspended jail sentence of 16 weeks after admitting animal welfare offences.