I had there roost a dowel because there almost 3 months but we changed it to 2 thick pieces of wood to make it bigger, thicker, and longer. The dowel was getting too small and kicking everyone off. So far they haven't fallen from what I see.
my girls sometimes get kicked off the roosts I watch this happen but none are hurt. I might give the coop a check an try to prevent this if it ever happens to me.