Sometimes contractors are entitled to notice of termination, and sometimes not – the answer foremost depends on the terms of the contract.
Because a true contractor is not an employee, the statutory minimum requirements for notice of termination to employees don’t apply and the parties can agree to any arrangement for notice.
If the terms of the contract do not address notice of termination, then the presumptions of the common law fill in the gaps. Independent contractors are presumptively not entitled to notice of termination, but dependent contractors are. The distinction between those two categories is not always clear cut. In broad terms, independent contractors operate an separate business and are not dependent on one buyer for their income, whereas dependent contractors tend to be more integrated into the business of their primary buyer and dependent on it for all or the large majority of their income.
Dependent contractors occupy an intermediary category between independent contractors and employees, which has arisen in the common law in acknowledgement that many workers are treated as ostensible contractors but are functionally very similar to employees.