MGM Poultry, the trading name for three farmers operating across Strathaven, Kilmaurs and Laurencekirk, will provide around 2500 free range chickens a week to Aldi.
Robert Morris, at MGM Poultry, said: "We started talking about working together in 2013 with the aim of providing a leading retailer with our quality, free range Scottish poultry.
"Aldi recognised the quality of our produce and we secured an annual contract which will provide a huge boost to the sector. The buying team at Aldi have been great to work with and it's exciting to see our product on the shelves across stores in Scotland."
Richard Holloway, managing director for Aldi in Scotland, said: "Working with local suppliers is very important to our brand.
"We work with a lot of farmers around the country and are very proud to be able to stock their fresh produce."
Separately, the latest Kantar Worldpanel data showed sales at Tesco and Morrisons have continued to slide.
The research, covering the 12 weeks to May 25, found both Asda and Sainsbury's grew although the overall market remained weak.
Asda, which is owned by Wal-Mart, was the big winner in the period as it booked sales growth of 2.4 per cent and was the only one of the big four grocers to increase market share, edging up to 17.1 per cent, from 17 per cent a year ago.
Sainsbury's saw its sales grow 0.9 per cent, but its market share slipped from 16.7 per cent to 16.5 per cent.
Consumers are shopping around to save money while also shying away from big weekly shops and buying more often in local convenience stores or online.
Tesco, Asda and Morrisons have all pledged to cut prices, while Sainsbury's has vowed to remain competitive, raising analysts' concerns about a possible price war hitting earnings across the industry.
Kantar said price cuts had also led to another drop in the level of grocery price inflation to 1.2 per cent, the lowest since May 2010. The research also found Lidl achieved a record share of 3.6 per cent in the 12-week period and its highest year-on-year sales growth, at 22.7 per cent.
Aldi's sales were up by 35.9 per cent with the company retaining the record 4.7 per cent market share it reached in the previous 12-week period.
Sales at Waitrose grew by 6.1 per cent and it also maintained its record market share of 5.1 per cent.
Edward Garner, director at Kantar Worldpanel said: "Despite the wider market slowing, Lidl achieved a record share this period, accelerating with its highest year-on-year growth. Similarly, Aldi has gained 35.9 per cent and retains its record 4.7 per cent share reached last period."