Osborne Building volunteered to do the labour free of charge with builders working by midday on November 14.
"I'm overwhelmed by the response," said Mrs Brown. "This shows businesses aren't there just to make money - they care about the community."
With a bustling menagerie of creatures at Wallowing Heights, it's hard to believe it all started with the Browns collecting "a few pigs" as a hobby.
That all changed in January 2012, when a hot air balloon struck powerlines killing 11 people, including the balloon pilot.
Among those who died were Chrisjan Jordaan and Alexis Still, who jumped from the burning basket, landing in the Browns' paddock.
Mrs Brown performed CPR, but the couple "died in (her) arms."
"Our home became an awful place after that - so tragic and sad."
Later, Mrs Brown noticed victims' loved ones admiring her piglets, while visiting the crash site.
"They would stop and say how cool the pigs were.
"So, my husband thought of starting a kids' animal park - as we heard Alexis and Chrisjan were big animal lovers.
"Plus, we wanted to change the atmosphere of the place."
Almost three years on, Wallowing Heights has "got a bit out of control" - now home to four heritage breeds of pig, a flock of Wiltshire sheep, three miniature horses, six types of rabbit, several dogs, an Orpington chicken and a talking Eclectus parrot named Pete.
It also has a section of "exotic" animals, including a bearded dragon, a pair of blue-tongued skinks and a chinchilla.
The Browns have poured about $200,000 into the park - but keep admission prices low.
Every shed, every stable, every animal has come out of the Browns' pocket, who source animals from all over New Zealand.
"Our credit cards are maxed. We've still got our day jobs.
"But we wanted to make it accessible, so we knew we wouldn't get back what we invested."
But the financial pressure is worth it for the "priceless" moments - and the joy on the Jordaan and Still families' faces when they come to visit.
"When Chrisjan's dad saw the children with the animals, he said 'I can feel happy again - my son's spirit lives on'.
"He told me, 'please keep this place full of kids'."