I'm not sure what might be going on for her, but about two weeks ago, I noticed that Bailey's back end was a bit dark. She's a palomino who's (whose?) coat goes sheer white in the winter. At first, I thought it might be from diarrhea (although she hasn't had a change in diet) but she has come into heat irregularly often lately, and the coloured area has grown larger and darker.
She is a healthy, open three year old. I will be taking her to the vet ASAP to get checked out, but in the mean time, what could be causing this? She is at the bottom of the pecking order, and we had a new gelding join the herd in September. (He established himself as #1/#2 in competition with my other female horse.) They are all rather mean to her (2 geldings, 1 mare)... could stress be pushing her back into heat and making her bleed or...? Bailey has never been exposed to a stallion, nor heavily worked. *sigh* Worried!
Thanks in advance!