Horse Eating Manure?

My filly, and the other horses she is in with, try and eat their manure. I am not sure why, or even if it is healthy for them...

I am pretty sure it is not their diet because they have good quality hay 24/7, water 24/7 and a salt block in there all the time. They did have a mineral tub, but finished it, but even while they had it she would try to... it is winter so they don't have grass.

I am thinking it might be boredom, but the horses do have each other to play with, and toys in there, like a jolly ball.

My main concern is there health, so is it okay if they eat their own manure. It is winter and it is frozen, but they still get some in them...

The biggest health concern is that they will be swapping parasites around. I would be sure that they aren't running out of hay. I would also give them a trace mineralized salt block as well as a loose mineral mix. Salt does not provide calcium and some other minerals.

This is one you might want to try:

http://www.unitedcooperative.com/ima...ineral1212.pdf

There are other brands that are similar that should be as good.

My QH did this for the first time ever late this fall - it was surmised that she was having some tummy issues I didn't know about, (possibly stress albeit 'good stress' when we brought my morgan here") I purchased a bag of Opti-Zyme (a probiotic powder) @ Tractor Supply Co., and gave it to her each morning for a month. She improved quickly, and no more eating poo! Really worked for her. Maybe give it a try, and good luck :)
*On a side note - I found out that no, it's not normal for them to eat manure, (of course), but they do it when having tummy problems - kind've like they're 'self-medicating'.

Their feed is lacking in nutrients. They need a trace mineral block.