Hey y'all! I have a 4 year old mare that is constantly rearing, especially in the alleyway.. But only when at rodeos. She does rear some other times when i'm working her, and i think she's just got a marey attitude and doesn't want to work. But Ive practice with her alone and she does awesome with going in and out of the alley. But anytime i go to compete, that's when she freaks. i've been doing this along time, so i'm not typically anxious myself going in. i'm very calm and soft handed, and don't try to cause stress on her. But i'm lost on what to do now. I don't know whether to try calming supplements or even a compression mask, but i'm desperate at this point! I need it to stop. 

Thanks in advance! 

Can you post a video?

More details would be helpful.

As a general rule of thumb, I would be searching for a PAIN reason on a horse that is rearing in the alley. Is she also refusing to go in?

Give us history on her. She's only 4 years old and you are already rodeo'ing on her? While there are exceptions, most 4-year-olds are NOT ready for rodeos. You could be pushing her harder and faster than she can handle mentally; thus resulting in the rearing.

You also say she has a "mare attitude" and "doesn't want to work". The majority of horses ARE willing to work so you've got to figure out why she doesn't want to.

Is she in pain?

Have you pushed her too hard?

Is she not ready?

Etc.

How long have you been running her? 

INBTMD

What???

I would love to hear a little more about your mare.

Edited because I forgot a word.

As others much more knowledgable than me have stated, I would make an appointment with a good performance horse vet and do a thorough lameness exam and rule out any pain. 

More details? I am curious too.