How To Measure For A Halter
Halters made by different manufacturers will fit differently...so you'll want to do a little measuring. Estimate where the nose band should be, usually a little over 1/2 to 2/3 of the way up between the horse's nostrils and eyes (just in front of the cheekbone). Using a tape measure or a string, measure around the 'nose'. Record the nose measurement. Starting at the side of the horse's face where the nose band would lay, measure from one side to the other, laying the tape along the horse's cheek, over the poll and to the other side. Record the crown measurement.
Once you receive your halter and put it on, the nose band should not be too snug. You want your horse to be able to eat and drink comfortably. Make sure the halter isn't binding. The throatlatch should not droop down too far, but you should be able to fit two or three fingers between it and the horse's jaw. It's important that it isn't so loose that the horse is able to get a foot hung when it decides to scratch with a hind foot or that it dangles making it possible to catch on something.