She can, if her US duties are primarily managerial: directing the plant's production function, supervising supervisory or professional staff, and holding authority over hiring, budget and operations. A manager whose time is mostly spent running a line personally does not qualify, whatever her title.
What decides managerial capacity in a co-packing plant
The regulation allows management of a function or department as well as management of people, but the petition must show the function is essential and that the director controls it rather than performs it. In a co-packing plant, that means describing the shift supervisors, quality coordinator and maintenance lead who report to her, and the line workers who report to them. It also means listing the decisions she makes: approving production schedules, setting the plant budget, hiring and disciplining staff, signing off on customer specifications.
Percentages of time help when they are honest; a statement that ninety percent of her day is managerial should be supported by the staffing that makes that possible. If the plant currently has four employees and no supervisors, the managerial-capacity evidence may be weak and the transfer may need to be delayed until the structure supports a primarily managerial role. Six years of leading the Canadian plant supports the foreign managerial role but does not substitute for evidence about the US one.