The selling shareholder is 81-year-old owner Bob Ingham, the grandson of founder Walter, who began the company in 1918 when he bought his son, also called Walter, a rooster and six hens. Bob Ingham put the company up for sale in July.

One in three chickens bought in Australia is raised on one of Inghams' 10 poultry farms and the company is also the nation's biggest supplier of turkeys and the largest manufacturer of stock feed. It had sales of A$2.2 billion in 2012, according to its website.

TPG's head of Southeast Asia, Ben Gray, described Inghams as "a great Australian business."

The companies didn't disclose the price but a person with knowledge of the deal confirmed reports of a valuation of around A$880 million.

TPG could invest less than A$200 million of equity in the operation once it finalizes debt arrangements with a consortium of banks. The lending consortium includes Bank Of America Merrill Lynch, Australia and New Zealand Banking Group Ltd., National Australia Bank Ltd., HSBC Holdings plc, Westpac Banking Corp., Macquarie Group Ltd. and Nomura Holdings Inc.

TPG's deal is the largest for an Australian agricultural business since July 2010, when CSR Ltd. sold its sugar and renewable energy unit to Singapore's Wilmar International Ltd. for A$1.75 billion, including A$403 billion of assumed debt.

Inghams tapped an Investec Bank (Australia) Ltd. team led by managing director Colin Young to manage the auction. The business attracted offers from TPG, Blackstone Group LP, Hong Kong's Affinity Equity Partners Ltd. and Sichuan, China-based agribusiness New Hope Group.

"An important part of the decision for me was finding a buyer who would ensure that our customers will continue to receive the highest level of service and our employees would be well looked after," Bob Ingham said in a statement. "I believe I have found that in TPG."

Inghams in February asked Investec to begin preparations for an initial public offering as an alternative to the auction after bidders failed to meet his valuation of more than A$1 billion.

The Ingham family will retain a large property portfolio and a horse racing operation.

In addition to Investec, Inghams took advice from PricewaterhouseCoopers LLP and legal counsel from Australia's Thomson Lawyers. TPG's advisers were Macquarie Capital (Australia) Ltd. and KPMG LLP. It took legal advice from Herbert Smith Freehills LLP.