Thousands of workers at Deere & Co, the world's biggest farm machinery maker, began picketing on Thursday for the first time in more than three decades to demand better pay as the company heads for its most profitable year ever. Representatives from the company and the United Auto Workers (UAW) union failed to reach an agreement over a new labour contract, which ignited the strike around midnight Chicago time. The move comes amid a labour shortage in the US, and as pandemic-induced chaos in global supply chains upends business as usual for manufacturers. But Deere stands out because it's enjoying boom times despite the challenges. Its shares have risen 38% in the past year amid a rally in crop prices that buoyed farmer earnings and demand for tractors. The company is set to enjoy its most successful year ever, with Wall Street analysts predicting record earnings minus items. During leaner times, employees made concessions to the company, the union said. Now it's time for the company to pay them back.