Good point Enduku. Funnily enough since I went barefoot about 4 years ago I never worry about kicks - it's shod horses who do the damage! However a mare in last stages of pregnancy - yup, you wouldn't want her kicked at all!
When I separated Merlot from the herd she grazed with just Persil until the last week before foaling when she went into her foaling paddock right next door to Persil. I have an electric tape alongside the fence so Merlot isn't tempted to kick Persil when he tries to befriend Zephyr, but they can still see each other.
I'm still waiting for the day when she stops pulling horrible faces at the Persil so he can go in with Merlot and Zephyr and Zephyr can then have a great playmate!