Well if (a very big if) you take one of the Priddy circles/henges that have been partially excavated, the third circle reveals, and the bank by the way is within the ditch; the ditch is u shaped, originally 3-4 ft deep and now probably 12 ft wide. The material from the bank was piled between two rings of stout posts and then roughly faced with locally collected dry-stone walling. I think the posts were estimated at 10 ft high... now on a 50- 50 basis was it a stockade or ritual enclosure?
And before Littlestone goes on more wild speculations.... Gorsey bigbury entrance is 13 ft wide, if it was stone gateposts we get back to the problem of hinges to hang the gates........... ;)

Surely a ditch, bank and stockade would be the most effective combination. Fence alone would do little, neither would a ditch or a bank alone, but the three combined? The fence would not necessarily have left much trace if it had been of the hurdle type. We can assume that any corral would have contained domestic animals rather than wild ones. So, with the exception of goats that are just about uncontainable, there is no need to envisage frantic animals hurling themselves at the barriers desperately seeking freedom. Just look at modern domestic animals in an enclosure. Are they trying to get out? They accept the barriers and don't challenge them. A determined horse or a bull could leap over or charge through hedge or fence, but they don't.