cutting back fawn bottles

At what point do I go from 3 bottles a day to 2 bottles. Most of our fawns are about 8 weeks old. They have greens, grain and water available at all times, they are eating some grain, lots of greens and drinking water. How much should I increase the feedings when I go to 2 times a day. They are currently eating 12 to 16oz at each feeding, 3 times a day. Seems like someone will skip a feeding some days, some would eat more if I let them.

Thanks Susan!