HAVANA, Fla. » Some of the world’s most rare and expensive chickens are bred on a 50-acre farm off a canopied road outside Tallahassee, Fla. Pitch-black Ayam Cemanis from Indonesia peck hands reaching for their $100 eggs, free-range Bresse hens eat greens and strutting Appenzeller Spitzhaubens flare their Dalmatian feather patterns.

On many days Sally Bradshaw, a 49-year-old Mississippian who lives here with her family, makes a point of walking by the chicken coops to visit a shed whirring with incubators. But recently she has been far away from the chickens and the farm, clearing a path for Jeb Bush to become president.

If Karl Rove was known as the charismatic George W. Bush’s brain, Bradshaw is the brainier Bush’s muscle. As Jeb Bush’s facilitator, enforcer and sounding board for 20 years, Bradshaw does the political trench work that allows her boss to keep his head in the policy clouds.

Just last week, the woman Bush called his "closest adviser for the entirety of my political career," helped drive Mitt Romney, for whom she once worked, out of the race by poaching his former Iowa director — all part of her mission to recruit top talent, raise millions of dollars and direct the policy rollout of the quickly evolving Bush campaign.

Exceedingly private — she often remarks that she would like to disappear to run a bookshop — Bradshaw speaks with a heavy Southern accent that masks a steely, direct demeanor and a knack for cutting to the quick. The daughter of a high school teacher and a dentist from Greenville, Miss., she has disciplined some subordinates in her previous roles as Bush’s campaign manager, chief of staff and overall top operative, putting red stickers on incomplete work, exiling enemies from Bush’s orbit and clashing with Rove over his failure to heed her warnings about Florida’s vulnerability in the 2000 presidential election.

"She’s kind of like a titanium magnolia," said her husband, Paul Bradshaw, a leading lobbyist in Tallahassee who also does the breeding and selling of chickens at what he calls the couple’s "peaceful, private home."

Bradshaw is highly esteemed by colleagues, and most of all by Bush, for her political instincts and loyalty.

"She has been integral to the decision process I am currently going through right now," Bush wrote in an email, describing Bradshaw, who declined to comment, as a straight-shooting "doer" who inspires her troops and "gets the best from people."

"I hope your piece reflects the great character and value she has brought my efforts," he concluded.

But Bradshaw’s propinquity to Bush, and the power she wields as a result of it, has also attracted a fair share of hard feelings. Her sparring with other Bush aides has created drama. Some Florida lobbyists grumble about her husband’s lucrative lobbying firm, Southern Strategy Group, the founding and rapid expansion of which coincided with Bush’s election as governor. And the consummate staffer has at times also emerged as a source of tension in Bush’s family.

Before Bush’s run for governor in 1998, he and his wife, Columba, were joined by Bradshaw and other campaign aides on a visit with Bush’s father and mother at the family compound in Kennebunkport, Maine. During the visit, Columba Bush questioned the amount of time Bradshaw was spending with her husband, according to people with knowledge of the meeting who requested anonymity to avoid angering Bush and Bradshaw.

Kristy Campbell, a spokeswoman for Bush, disputed the account.

"Sally has enormous respect for Mrs. Bush," she wrote in an email. "And Mrs. Bush respects and appreciates the role Sally has long played as a political counselor to the governor."

The moment of tension passed and Bradshaw remained Bush’s top adviser. And now the couple has entrusted Bradshaw to bring them to Washington.

It is a destination that Bradshaw knows well. Her first boss was Webb Franklin, a Mississippi congressman, who said her parents were Republican donors and activists — "big Rs," he called them. As a student at George Washington University, she interned with Haley Barbour, the Mississippian who was then director of political affairs in the Reagan White House, after he received a call from Bradshaw’s uncle, a former law school classmate and drinking buddy. Bradshaw joined George Bush’s 1988 presidential campaign, and first met Jeb Bush when she picked him up at the airport to bring him to a Mississippi fundraiser. He made fun of her Honda Accord.

When Bush’s father became the 41st president, she worked as a southern liaison in the White House political affairs office. With her roommate Kimberley Fritts she entertained the Bush administration’s "southern mafia" of operatives. They also drank red wine, cooked casseroles and finger foods.

"She was like a dip queen," said Fritts, now the chief executive of the Podesta Group, a powerhouse lobbying firm.

In 1991, Van B. Poole, the chairman of the Florida Republican Party, began trying to lure Bradshaw to Florida, telling her "she had a heck of a future," Poole said. That future would be with Jeb Bush. Bradshaw was the obvious choice to help him, as she had written a party manual about fielding and training candidates in the state.

After losing the 1994 race for governor, which Bush ran as a "headbanging conservative," Bradshaw signed on for a second campaign. Along with Bush’s media consultant, Mike Murphy, whose girlfriends she used to vet, Bradshaw helped recalibrate Bush as a more moderate candidate focused on education reform. That approach was also a better fit for Bradshaw, who is conservative but not particularly ideological. Her former Presbyterian pastor, the Rev. Tom Borland, described her as a "force for unity" who urged him to preach his convictions when some conservatives left the church over his support for same-sex marriage.

When Bush was elected governor in 1998, Bradshaw became his chief of staff and gained a reputation for long hours and an inclusive management style. Together, they tackled big policy issues, including cutting taxes, expanding school choice and shepherding the One Florida program, which Chris Dudley, a former deputy chief of staff, characterized as "essentially Jeb getting rid of affirmative action."

Dudley, who is now a lobbyist at the Southern Strategy Group and will host a fundraiser for Bush this month, recalled a Saturday morning at the governor’s mansion when Bradshaw and Bush solicited ideas for the One Florida program from all 15 people in the sunroom.

"At the end of the day it is probably Jeb Bush and Sally in the governor’s office making the final decision to pull the trigger," Dudley said.

Bradshaw left the governor’s office in 2000 to give birth to her daughter. By all accounts, she has been an attentive mother (she also has a son from a previous marriage and is stepmother to Paul Bradshaw’s two children) even as she continued to advise Bush and local and national Republicans. In 2008, she was a Florida strategist for Romney’s campaign but grew frustrated with the lack of resources the national headquarters sent her way.

In preparation for 2012, she made it clear to the Romney campaign that her first allegiance was to Barbour. When the former Mississippi governor’s nascent bid fizzled, she focused on local politics, hosting the incoming Florida state Senate president at her farm to urge him not to "surrender accountability" on grading standards, a hallmark of Bush’s legacy. After the presidential election, she consulted on the party’s autopsy on what went wrong with Romney’s campaign.

Bradshaw stayed in touch with operatives around the country, including Beth Myers, her senior strategist counterpart in Romney’s political universe, and last fall the two had a long talk about the Bresse chickens Myers had learned to cook in Paris, and that the Bradshaws had eaten in France and raised on their farm.

"We talked about how wonderful they are," Myers said of the chickens.

Bradshaw spent most of 2014 taking calls and fielding emails from operatives and donors around the country who expressed interest in working for a potential Bush presidential campaign. As recently as November, Bradshaw was putting Bush’s chances of running at 50 percent, according to people with whom she had lunch. But around Thanksgiving, Bush activated Bradshaw to lead his PAC, and in recent weeks, to squeeze out Romney.

"I was calling the same people she was calling," Myers said.

She’s hardly finished. Wayne Berman, a Republican bundler who is committed to Sen. Marco Rubio, said that he has had several "lovely conversations" with Bradshaw, who he considers a remarkable political talent. Rubio will probably soon decide if he will run for president or for re-election, in which case his donors will be newly available to Bush.

"People who are committed to other candidates trust Sally," Berman said.

As Bradshaw accompanied her boss around the country, her husband was back at the farm explaining how he had helped conserve the Olandsk Dwarfs, of which he said, "There were once 54 of them left in the world." He insisted that his wife was "interested" in the chickens but allowed that a Bush candidacy might have a greater claim on her imagination.

"If you do what she does for a living, this is the Olympics," he said. "And you make sacrifices for the Olympics."