I have never personally dealt with a bleeder however I suspect my 5 year old futurity mare may have a problem.  Yesterday a a local fun show my friend noticed blood coming out of one side before I went in the arena.  Is it possible to bleed before a run?  Like I said I have never experienced this before. A little backgound- Up until last weekend at State Finals she has become more anxious at the gate- not terrible but still more anxious.  At State Finals she lost her mind in the warm up pen and stared rearing.  I know there was alot more horses and music than she had been accustomed to.  We never even got to run because she reared in the holding pen.  The gate guy grabbed her and put her in the alley and we took off only to get around barrel 1 and start rearing again. I did not notice any bleeding but to be honest I was not looking for it.  I took her all 3 days and we spent time in the warm up pen trying to acclimate her to the noise and action.

I know my nerves are not good now due to her behavior so that is not helping the situation.  I am going to have her vet checked as soon as I can get her in but wanted to hear some opinions.

Have her scoped after a run by a qualified equine vet 

My granddaughter's horse bled for the first time this weekend.  He is the most laid back, calmest horse we have ever owned.  Never been hot a single time. Now we are wondering if he has been a bleeder before.  This time was massive.  He coughed up blood and from his nostril.  He is going to the vet tomorrow but we have never dealt with anything like this before.