If you look at thread titles, far to the left of them you can see their status. A little padlock means the thread is closed.
Threads get closed if there is a threat, obnoxious behavior, excessive fighting, or anything admin deems inappropriate for YorkieTalk. I love how they take care of things around here.
If it is a thread that recently got locked about horse bites...I think it was because there was a personal threat in the thread.