We foal out anywhere from ten to twenty mares a year. My sister and I do all the birthing and the foal watch. I do not enter the stall until the mare has the foal's front legs out and working on the head. (Of course, there have been times when a mare has just taken too long to get anything out and I go in for a presentation check. Only once, after all these years, have we had a leg back that needed to be fixed.) Anyway, once the mare is really struggling on her own to push the foal, I help gently. There is a right way to help a normal birth and there's a wrong way.
Right way: Give little tugs WITH the mare's contractions. Mare's take lots of little rests between pushings, so do I. The key is be gentle! Then, I'm right there to lift the sac off the baby's face and keep it's head out of the stall bedding until he is fully out.
Wrong way: PULLING with all your might with no rests in a NORMAL birth is wrong. It will tear and damaged the mare's vulva and possibly her cervix. Granted, in emergency situations, pulling with all your might is definitely necessary and correct. It's hard for me to watch some MareStare cams, because it appears that they are pulling unnecessarily hard with no rests, but it may just be the camera, the angle, we never know what's really happening. I still watch. lol It's MUCH more frustrating and unnerving when people are standing outside the stall watching a mare struggle and flounder about for a long time without helping or checking her. Argh!
A good horse is worth more than riches. ~ Spanish Proverb