Please Welcome the Next Candidate
By adding some fuzzy logic, the areas where the young dragons settle could be varied (as in nature), as could the intervals – e.g. as a figure of the time of year – and thus camping becomes not viable. Players would have to walk around a bit to find a dragon, work out any migration routes, or maybe rumours would spread when it was known where a flock of the young dragons had settled. This takes a bit more programming than the spawning solution, but might it be worth the effort?