Muslims... Oh! sorry thats another group..
John ch 10 pretty much explains the Sheep pens, those in them and those that came out to follow the shepards voice.. but no doubt about it.. They be a buttload sheep in them pens.. All kind of pens.. i.e. denominations.. There be denominations of goats too grasshopper.. but thats another story.. A sordid tale it is too..
Do you post on factnet message board by the user-name skooter942000
Okay, just for giggles, the explanation I heard of that parable (and it was not from no Cat'lick neither) was that LOTS of flocks were put into ONE fold for safety's sake, and then when the shepherds come and lead them out to graze in the AM, the sheep know their shepherd and follow him.
It's certainly true that sheep are more docile around someone they know.
My sheep tended to follow me, because they knew that most of the time if I was leading them somewhere good food and water were at the end of the walk. And they sure wouldn't follow anybody else. (My goats only followed me if they wanted to be milked or if they felt like it. WAY more cat-like than sheep are ...)