That depends on what you consider “difficult” and what industry you are in. The process is not simple enough to navigate on your own — you’ll most likely have to contact a law firm like this one to help you sort out what type of employment visas work best for what you have in mind and how to obtain them. There will be a lot of paperwork to deal with.
And as mentioned, the industry you’re in will also impact how hard it is to hire foreigners. There are different requirements for seasonal agricultural workers when compared to hiring financial professionals or researchers, for example.
The good news is that hundreds of companies hire thousands of foreign workers with the help of attorneys every year. Meaning there are a lot of good immigration attorneys and law firms to choose from, and they can help make the process as simple as it can be.