I had the same problem with my mare just one year, only when she was in season. However there are a few reasons you need to examine before you try and do anything; while these may not be the case it is always very important to make sure the horse is not in pain before trying to anything which may just cause more physical and emotinal harm. Firstly, check all the areas that may be causing distress or comparing this behaviour to what she usually does, for example:
- Have I checked that her ears are ok, with no insects or cuts?
- Have I checked that her teeth are not sharp and I have had them regularly seen to by an accredited equine dentist?
- Has she only just begun to start this behaviour, or has she always done this (NOTE: if she has only just started, is there anything you have changed, done differently or a negative previous experienced she has encountered?)
- Is my mare on heat, which can cause her to be more temperamental?
- Is the bit too sharp or is there something on the bridle that could be causing her discomfort?
If any of these are the case, then try and find the solution to the very source of the problem first. However if there is nothing else you can do, then perhaps try putting toothpaste on the bit so she enjoys having it in her mouth. Or talk to her nice and calmly when you are putting the bridle over her head- you could even gently sing a soft song or lullaby in attempt to calm her and show her that you are not nervous. We did these things with my mare, and while it did settle her down a bit more, we enclosed a corner of her paddock so that it is enough room for her to turn around in a full circle with a little bit of room in case you need to shift, but not enough that she can continually pull away and run around. We kept of trying again and again until eventually she just had enough of fighting and finally accepted the bridle. As soon as you do get the bridle on, remember to give lots of praise and rewarded her- massage her ears if she lets you and tell her what a good girl she is. Make sure she knows that having the bridle on is a positive experience and something to look forward to. Sam with when you do manage to get it off without her making as much as a fuss- since the bit is then out, give her a small treat and again reward her.
It takes time and patience but remember whatever you do, especialy if she is in season, do not 'loose your cool' with her and begin getting angry with her as then may associate that pain with the bridle. Good luck and I hope everything goes well