That sounds like a good plan for my mare. She starts bagging up a month before hand and keeps her bag the whole month.I clip like I marked in the picture on both sides and the entire underbelly..
I usually just clip up around the flank when I notice udder development, much easier to keep a visual on udder change without the long hair.. When they have a decent udder that I think foaling will be within 2-3 weeks I clip the belly.. I've had later foals the past couple years so haven't really had to worry about the belly clip as most of the girls have blown/shed their coat by then.. I'm hoping to get a couple of the girls bred for earlier babies in 2012
Looks like I'll be clipping around day 300!