Pony Problems

Question
I am a Park Ranger at a small zoo/farm. We have a 7 year old Red roane Appaloosa Pony named Mayflower. Our problem is, recently she has started being aggressive toward one of our employees. to the extreme that she will rear kick and show alot of aggressiveness. I went to her stall today and she was even getting snippy with me. This is very unusual for her. i have been here 4 years and never had a problem. Yes, she's a pony and she can be stunnorn, but never this aggressive, especially at me. i have thought of trying the treat method and having the new guy try it as well to establish "leadership", but i would like a professional's opinion before we try anything. Thanks in advance for any help you can give. Kristine

Answer
Hello Kristine,
I have a couple of questions for you on this mare.  Do you work her frequently or is she kept in a stall alot?  Also has there been any new additions to her housing/environment as well as any newcomers such as new horses?  Any changes to her riding program and or feeding routine? Does she look to be in pain at all or have you noticed a change in her gait,riding etc..... Get back to me when you can with these answers and I will have a more definitive answer for you to approach the situation and get it handled more effectively.  Thank you Kristine.