These docs are for an old release.
Info on upgrading to v4
renderEvents 3.1
Renders multiple new events on the calendar in batch.
.fullCalendar( ‘renderEvents’, events [, stick ] )
This method is similar to the renderEvent method though it accepts an array of events as its main argument, to render multiple events at the same time. This reduces the number of event rerenders that must happen, for performance reasons.