Just went back to look at the pics again on the previous page, and Diane's repeats of the udders here. Would say that Silver is very pregnant for a maiden mare, and Wish looks close to foaling for a mare who has had foals before, not easy to say who will foal first in my opinion due to the maiden against brood mare tummies! Regarding their udders, a lot of my brood mares have 'separated' teats all the time, so I was not looking at Wish's separated teats, rather that she appears to have an 'empty' udder as against Silver who seems to be filling one side of her udder - looking at the 'smoothness' of that one side.
Hope this makes sense LOL!! Just my opinion. How do their udders feel to you, can you feel any filling?