BREAKING A 4 YR OLD

Question
I HAVE BEEN BREAKING HORSES FOR 3 YEARS AND I HAVE RAN ACROSS A MARE THAT IS GIVING ME MORE TROUBLE THAN ANY OTHER HORSE I HAVE WORKED WITH. I AM BREAKING HER FOR A LADY THAT IS SCARED OF HER AND THE HORSE IS SPOOKED HERSELF ON TOP OF THAT SHE HAS A 2 MONTH OLD COLT BY HER SIDE. I HAVE TRIED WORKING HER IN THE ROUND PEN WITH AND WITHOUT THE COLT BUT SHE HAS A PROBLEM WITH REARING UP REAL BAD. SHE IS PROGRESSING EVERYDAY BUT HOW CAN I STOP HER FROM REARING UP. I'VE HAD HER FOR ALMOST A MONTH NOW AND JUST FINISHED THE GROUND WORK. PUTTING A SADDLE ON IS NO PROBLEM AT ALL. IT'S JUST SHE REARS UP WHEN I GET AROUND HER. WHAT CAN I DO TO STOP THAT??

Answer
Firstly I have to ask  why if the owner is scared of her is she having  you do the breaking of her, is she going to be any less scared when the horse is broken in?

You have to remember that she has a foal with her, a young  one at that.  Her hormones are all over the place at the moment, so maybe breaking her right now may not be the ideal time to try anything very complicated.

You say you have finished the groundwork inside a month, not a very long time to give the groundwork and reinforce the lessons.   

You also have to ask what (if anything) are you doing to cause the rearing problem in the first place, is there something in her past, is it a defence mechanism.   Assuming that its not her past, and assuming you  have done nothing to cause the rearing in the first place, then I can only conclude its some  kind of defence mechanism as in 'don't hurt my baby or I will hurt you'

Theres no fast and easy answer, you are just going to have to try patience and kindness and be firm but gentle with her on this one.  every time she rears up at you then display very negative body language, she is doing this so you  will take notice.  Tell her NO in a very firm and mean it voice every time she rears, DO NOT smack, whip or punish her in any way.  If you are working in the round pen then every time she rears send her away again until she is willing to come to you and conform  to your ideas of behavior not hers.

The negative body language from you will reinforce this message and in time she will learn that this behaviour is getting her nowhere and is non productive, as I said it may take some time but it will be time well spent for the future.  

Hope this helps