6/2/2021 By Nandita Bose and Tom Polansek WASHINGTON/CHICAGO, June 2 (Reuters) - JBS SA employees started returning to U.S. meat plants on Wednesday, a day after the company's beef operations stopped following a ransomware attack, disrupting meat production in North America and Australia. A notorious Russia-linked hacking group is behind the cyberattack against JBS, a source familiar with the matter said. Brazil's JBS controls about 20% of the slaughtering capacity for U.S. cattle and hogs, so the plants' reopening should prevent a severe supply-chain disruption. JBS, the world's largest meat...