I agree as Slaney and Shimmer were going along with the same udder, shape etc and then like you flicked a switch they got their game face on and foaled within a couple of days once they started the final bit of udder filling, shape changing, jello bum etc.
Once they hit a certain point in their development then the rest can happen very quickly.
I cant wait for Suzie and Peanut to foal and see the gorgeous babies.