Now, during season is a whole different issue. I remember reading that one of the issues that lead to Ethan Stiefel's departure from NYCB was his inability to get permission to do guest appearances during 'Nutcracker' season.
This is a perennial problem throughout the ballet world. For a given male dancer at a certain level, someone will ALWAYS pay him a LOT more for guest Nutcracker appearances than his company is able to pay him week-in, week-out for the rest of his dancing.
I've seen guys with no more than 1 or 2 years professional experience get payed up to $1000/show for Nutcracker guesting, plus travel expenses. A weekend can net 3K EASILY. For a company in which the entire Nutcracker season pays only $3-6K, this is nearly irresistable for the starving dancer. Almost always, the company paying huge sums for guesting is not of same caliber as the "home" company.
Ethen Stiefel made a LOT more than that, both for dancing at NYCB and for guesting. But the math and incentives are still the same. And when the next Spring rolls around and high-priced guesting opportunities have evaporated, you will certainly get hired back for the regular (non-Nutcracker) season, which is more interesting anyway. Because they need men.
It's perverse, but there is a real disincentive to stick around with a quality company for Nutcracker. There are no easy answers to this problem but all companies face it. NYCB sought to draw the line on this kind of guesting, and they lost Ethan Stiefel for it. That may not have been such a bad management decision, given NYCB's tradition and heritage. In Balanchine's time, Balanchine himself was the only irreplaceable person at that company.
The other big guesting opportunities come in the late Spring, when all the semi-professional shows go up. If you can do Swan Lake and Coppelia and the rest of the standard classics on moment's notice, you can make a lot of money in may and June that way as well.
For a dancer who was nothing like Ethan Stiefel (but still quite competent), I've seen men make a steady $30-40K/yr just from guesting --- and that's only working maybe 12 weeks out of the year. Once you've made a string of contacts, you can just do them year after year, like any other consulting lifestyle. No ballet company can compete with these prices on a regular basis.
On the other hand, everyone seems to agree that guesting around is not as rewarding, artistically, as dancing regularly for a company.
And ABT & NYCB has and will have dancers from Russian, Danish, Dutch, British and other European companies dancing with them.
Does NYCB do this? If so, it's a departure from their past tradition. ABT is well-known for bringing in and promoting stars from around the world. That's what makes them distinctive as ABT. But historically, NYCB has sought to work with its own company.