Dr of BBQ
Most of the chicken type rotisseries are 3 phase, which requires special electric hook ups and to the best of my knowledge can not be run off a generator.
That said some can be changed to standard 220 volts with out a great deal of expense. But get your favorite electrician to look at the unit before you buy it to be sure it can be modified. Or if your buying new you may order a standard 220 volt unit.