The "Mechoui" feasts I've seen here in the Périgord have most often been lamb (looked like a fairly mature lamb to me) spit-roasted over a big bed of coals. For hours and hours. I saw one being advertised earlier this year which was a Mechoui à Sanglier (wild boar). 'Though the authentic Moroccan version may well be pit-roasted, what I've seen here is spit-roasted.