From personal experience, I've bought this brand of farmyard manure for the past few years, and there is lots of woodchip present. Didn't think it would be an issue until I read what the RHS had to say.
Yes, I do, but you asking this question tells me you have no idea of what happens at a Horses stable.
You know any ideal what horses eat?
Difficult to get cow manure, horse manure is easy, but that is likely to have lots of wood shavings
Alternatively, just ask for your local farmers stables (poo) . At least, you know where the (poo) is coming from. Make sure it's well rotten for a while. (y)