Either is available to a Canadian citizen. An in-person application at a land border or preclearance facility produces a same-day answer with no visa required; an employer petition on Form I-129 takes longer but leaves a written record and a decision that can be reviewed before anyone travels or resigns.
Choose the path that matches how much certainty the household needs
The trade is between speed and evidence of the outcome. Presenting in person is fast and inexpensive, and for a clean file with a well-drafted letter it is usually the sensible route. It also means an adverse decision arrives while standing at a counter, with a household that may already have given notice.
A petition filed by the hatchery costs more and takes weeks, and premium processing shortens that at the price listed in the fee schedule, but Marguerite would know the answer before selling anything or ending a lease. Two intermediate arrangements should be avoided in either case. Beginning the American work remotely from Prince Edward Island while the file is prepared muddies who employs her and from when.
Travelling to help commission a hatchery run as a visitor, then doing productive work while there, is a separate problem with worse consequences. Neither should be improvised without advice.