His mother, Theresa Robinson, grew tired of commuting from Mount Dixon, the family's fat lamb and wool farm near Gunning, into Canberra for her public service job, and getting William to and from the doctor and hospital to have his adenoids removed and grommets inserted.

"I would be up during the night, having to drive to Canberra with hardly any sleep the next morning, and ran off the road one day," Mrs Robinson, a mother of four children, said. "I had a micro sleep, I didn't injure myself, it was a wake up call that I had to do something else."

Hatching a plan to work from home and grow food in the backyard, she bought 50 hy-line chooks and fashioned nesting boxes out of broken milk crates. One morning, lo and behold, she came across her first egg. "I raced inside, I was so excited, and showed my husband, Craig," she said.

Two months later she delivered surplus eggs to a Gunning service station, then more to the village's cafe. By December 2013, they had ordered another 100 chickens, were selling to a shop in Weston,  and had refined their marketing, starting with an illustration of an egg-laying chook with smoke curling out from its backside.

From the Yass area, Mr Robinson's family have always called eggs bum nuts. So the couple kicked that theme around before coming up with a chook firing an egg out her rear end under the logo: Gunning Bum Nuts. They were on fire.

"We got another 350 chickens, after that another 1000, then another 1000, and another 1000 and another 1500. We have about 5000 at the moment," Mrs Robinson said.

"The name, logo and slogan, 'bloody good eggs from free range happy chooks' were the drawcard," she said. "People thought 'oh, we have to check this out'. Then they have cracked open an egg, noticed how it holds together when you are poaching it. All of our eggs leave this property no later than three days after they are laid."

Majura Valley free-range egg farmers Nick Weber and Anne McGrath mentored the Robinsons. "They are lovely. You start talking chickens and Nick, you can't shut him up. He has been a wealth of knowledge," Mrs Robinson said.

Mr Robinson converted an old caravan into a roosting shed, and has since built mobile sheds, which are rotated around paddocks, giving each chook 10 square metres of space.

On their 377-hectare farm, four people have part-time jobs packing the eggs. Four maremma dogs ward off foxes and two pairs of wedge-tailed eagles. They are all about to get busier, because Gunning Bum Nuts has spread to Sydney. They have a new distributor and will scale up to 10,000 chickens. They expect to be selling 1000 dozen eggs in Sydney. A franchise is beginning too, in Bundaberg, Queensland, under a Bundy Bum Nuts label.

The soothing chatter of thousands of grazing chooks could be smashed soon. A developer wants to use a neighbouring property for a motocross track and spectator facilities for motocross, enduro, minikhana and trail bike riding on Wednesdays, weekends and public holidays.

Upper Lachlan Mayor John Shaw says activities are increasing in the shire, which straddles the Hume Highway, because of high land prices in Sydney, causing people to look inland. Two development applications have been lodged for separate motocross facilities in separate areas of the shire. The Robinsons and neighbours fear noise, dust and biosecurity breaches will compromise their tranquil, productive surroundings.