Suzanne Atkinson, 54, was among those charged by the Canadian Food Inspection Agency after the Shropshire sheep were removed in April 2012 while the farm near Trent Hills, Ont., was under federal quarantine.
The farm was suspected of being contaminated with scrapie, a fatal neurological disease of sheep and goats.
Atkinson, along with 56-year-old farm owner Linda Jones, 60-year-old Michael Schmidt and 48-year-old Robert Pinnell, were initially charged with four offences.
Atkinson pleaded guilty and was convicted Monday on one count of transport or causing to transport an animal under quarantine, and is to be sentenced Jan. 30.
The three others are still before the courts on that charge and conspiracy to commit obstruction of a CFIA inspector, conspiracy to transport or cause to transport an animal under quarantine and conspiracy to defraud the public of a service over $5,000.