One-legged ducks, arthritic sheep and goats with joint problems are among the 172 animals cared for at the farm.
One resident is a sheep called Dumpy who has a deformed jaw after he grew teeth big enough for a horse. However, the problem was not clear when he first came to the centre.
"When he arrived he was under a year old, so his teeth hadn't fully grown yet", said Mrs Slaney.
"The deformity would probably have never been seen because his whole family would have been on a plate before the issue was clear", she said.
Mrs Slaney had a career in marketing before starting the farm. Mrs Slaney and her husband purchased farmland by their house and chose to return it to its original use by repopulating it with livestock.
They never wanted to use it as a working farm, so chose to use it to rehome disabled animals who could not be housed elsewhere.
They began by taking in chickens before expanding to larger animals like donkeys, goats and sheep.
Dumpy is one of several sheep on the farm who have been saved from the slaughterhouse.
"Animal attractions get rid of sheep past the cute stage", said Mrs Slaney.
"They are used for bottle feeding in the springtime or nativity scenes at Christmas. But after that they're a drain on resources, so they go right into the food chain."
"It's an unseen nasty thing behind the scenes.
"It should be explained for visitors going to this place that animals aren't living long and happy lives there, particularly sheep who have a high value as food.
"It sets your mind wondering as to what would happen to these animals if they lived another four or five years. Normally in farming no problem would show, if it did they would sent straight to slaughter."
Other residents of the farm include Stumble, a one-legged duck, Ronnie, an overgrown goat and Dylan, a sheep with arthritis.
A partially-sighted pig called Simon with deformed legs came to the farm three years ago from a shelter where he had been living with bigger pigs that "bullied" him. He now lives with a smaller kunekune breed pig called Brooke.
Several animals require intense care to deal with their problems. A sheep named Hattie needed two weeks of rest in a private stable and treatment twice daily after suffering from a granuloma on her foot.
The centre called her a "superstar" for dealing with the condition.