I don't do imprinting either. I watch on monitor while the foal is born, and I don't interfere until the foal and mare are back on their feet, and preferably, not until the foal has nursed at least once. Then I go in and do a quick once over, check the placenta for completeness if it's detached, and if so, I remove it and get out til the next day. So, I actually try not to bother them more than necessary but if mom is not welcoming and gives me ears or the "blue eyed death stare" that Boo is so famous for, halter on and tied up for just a couple of minutes. I've foaled out some pretty aggressive, well actually nasty, mares and learned the hard way that I don't tolerate any attitude or interference from the mare.