Introducing foal to other horses

Question
When should I put my 2 1/2month old Filly and 7 yr old dam out with my 10 yr old mare? The dam & mare were inseparable before the 7 yr old  foaled. The 10 yr old mare is the dominant one of the 2, so I'm concerned about the filly getting in the middle of a scrap. Am I better off letting mama protect baby, or wait til the filly is weaned??? I am not sure when is best.

Answer
I'm not an expert on behavior but I would stay on the side of caution with this and wait until the foal is weaned. You might introduce them briefly each day for a short time and increaase the time but if you tried this i would be sure that you or someone can oversee it and be nearby to take the foal out if necessary. good luck with this.