So glad this topic came up this is a little off the question but, just wondered if anyone else has had this happen and to say this is something you might want to watch for.
I do as the rest of you but, since straw is hard to find i am sure this could happen with straw too. You all know how curious foals are and mine seem to like to imitate mom so mom eats grain and the little darlings do too and same with the hay and since they don't have the ability to chew good when newborn what they do is move it around in there mouth the first time this happened to me what i noticed was a little sprig of hay protruding from the corner on there mouth and they acted like they were trying to swallow or sort of like choking I stuck my finger in the mouth and was shocked to feel a big wad of hay way back in there mouth and attached to the piece sticking out of mouth. I pulled it out and was amazed at how long and how big the wad of hay was I am sure it interfered with there ability to swallow the milk and also observed they were not nursing well ,which was what first prompted me to check the mouth. Now I routinely check there mouths they really get huffy with me, but I am not taking any chances I am sure they could really choke if it was not removed. I have watched them as they lay for there naps and to rest i see them nuzzling or nibbling the bedding that is under there mouth as they rest it in the bedding.I have seen this happen a lot so always check mine as I want to be sure they nurse .If you see the mares bag getting really full and dripping it is possible the foal is not nursing due to this being in back of there mouths.