I went out to the barn a few weeks ago and my gelding had a lump a little above were his neck meets his chest. I poked and prodded it for a while and didn't seem to cause him any pain. It's about half the size of a potato and you can sort of pick it up under the skin and its more hard than soft. It hasn't changed in a while and still doesn't bother him. Other than the lump he has no symptoms of any diseases I know of. Any ideas what it is?