By George Ramsay and Alex Thomas, CNN

(CNN) -- When asked what he planned to do after retiring from rugby, Kevin Barrett -- or "Smiley," as he was nicknamed -- announced he was "going to breed some All Blacks."

A bold statement, but he did just that. Three of them, to be precise -- the first trio of siblings to ever start a game for New Zealand's hallowed rugby team.

Beauden -- a World Cup winner and two-time player of the year -- Jordie, and Scott made history when they linked arms to sing the national anthem before taking on France in 2018.

It's not uncommon for two brothers to line up for the All Blacks -- 46 sets have done so in the past -- but for a single family to have such a foothold within the current team is unprecedented.

Good genes certainly play their part: Dad Kevin was an uncompromising second row forward in his playing days, turning out for provincial side Taranaki 167 times, while Mom Robyn was a strong runner and a talented netball and basketball player.

But growing up on a dairy farm on the west coast of New Zealand's North Island did its bit for the boys too.

"It certainly helped just having acres and acres of green grass, a back lawn where there's goal posts and plenty of siblings and cousins around to compete with and play against," Beauden, who has over 70 All Blacks caps to his name, tells CNN World Rugby.

"I think that the only thing that mum ever forced us into doing something was dropping us off at the top of the road and grabbing our school bag. She'd give us a pair of sneakers and say, 'Run home.'"

But on the playground that was the family farm, shoes were unnecessary. Barefoot running was usually the way the siblings roamed the pastureland surrounding their home.

"I was more than happy to not wear shoes. The only time we wore shoes was on Sunday when we went to church," says Beauden. "Our feet were pretty tough back then, I couldn't do it today."

Swapping sports

A competitive urge came naturally to the Barrett boys, often at the expense of Jordie -- the youngest of the family's five brothers.

"Most of them aren't very nice memories, I spent a lot of the time crying and trying to compete and be as good as my older brothers," he says.

"But it was a very good position to be in. I was lucky, I always had boys to kick the ball around with or play backyard cricket with so that was a pretty cool position to be in."

There are eight Barrett siblings in total, each of whom carries the sport-obsessed genes. Kane, the eldest, was a talented rugby player turning out for Taranaki and Super Rugby side the Blues before concussion forced him to retire early, and Blake, the fourth brother, also plays at the local club.

There are then three younger sisters who enjoy swimming, netball, and dancing.

Even the family's rugby internationals continue to flit between sports today. Jordie and Beauden speak with CNN at the T20 Black clash, a charity cricket game pitching the country's best cricketers against its rugby stars. For Jordie, who lashed a 42 not out at the crease and picked up two wickets, both sports come easily.

"In the end, rugby just made a decision for itself, really," the 22-year-old says of a potential career on the cricket pitch. "I enjoyed my cricket growing up and played it right until first year at university -- basically until I couldn't play both, and it was as simple as that."

'A shiver down your spine'

That three brothers from a rural corner of New Zealand have all gone on to play Test rugby is credit to the country's pathway system.

It's not just that New Zealand, with a population of little more than four million, excels at rugby's elite level. Pitches are everywhere and clubs are in nearly ever town. Rugby is in the country's lifeblood, and boys and girls of all ages dream of playing for the national teams.

"I just remember, it seemed to be the thing to do to get up a three o'clock in the morning and watch the All Blacks play England or South Africa," says Beauden. "It was just part of who were, and I imagine it's the same today.

"I think New Zealand Rugby do an exceptional job, the way it's set up from the All Blacks, right down to grassroots. There's a clear path young players can take if they want to be an All Black, if they're talented, or if they get opportunities."

There's a pretty convincing argument that the All Blacks are the most successful sports franchise in history, boasting a better record than Brazil in football or Australia in cricket. Their 125-year win ratio is over 75%, more than any other major national sports team.

Engrained in the team's identity is the haka. Performed before each game, it was originally a Maori ritual undertaken by the country's indigenous people ahead of battle. Today, it unites the All Blacks -- many of whom are from different ethnic backgrounds.

"Whoever does the haka, it sends a shiver down your spine," says Scott, who made his international debut in November 2016. "It gets your blood boiling and that's what you look forward to -- the time before games. It's something special, for sure."

"When I got on the field it just happened so quick and I loved every minute of it because that's what every Kiwi boy growing up wants to do -- play for the All Blacks. It's a dream come true."

Tasting success

New Zealand has been the top-ranked side in the world for close to a decade and this year will go in search of a record third straight World Cup win. It won't be straightforward, though.

Northern hemisphere rugby is in a stronger position than ever with Ireland defeating the All Blacks late last year and England and Wales also running hot.

The three Barrett brothers are likely to all feature in Japan this year. While they admit time with the whole family together can be difficult to come by, a victory for the All Blacks would no doubt bring them all together.

It did when Beauden, a try-scorer in the 2015 final as New Zealand beat Australia at Twickenham, brought the Web Ellis cup back to the family farm. Celebrations saw Dad fill the trophy with milk from their cows.

"Creamy white milk looks so good in the gold cup," says Beauden.

You imagine victory this year would taste pretty sweet, too.