My girls have started 'riding' each other. I'm not sure if this is a sign that they're in heat or not, but I'd like to know since I was thinking about breeding them. Thanks for your advice!
Sheep are difficult to catch in heat but in instances it can be a sign. In my experience it's best to put the ram out with thm for a couple of weeks. A lot of goat breeders are capable to take the goats to breeders for an hour or two but sheep don't really work that way due to their pretty silent heat cycles.
It is easiest if there is a ram in there. The ewe in heat will hang around him, pee for him, point her rear at him etc.....next day she won't want to know him!