Weird bump???

Ok so I did a full body clip on my 4 or 5 year old miniature horse mare and found a strange hard lump about an inch and a half long on her ribcage... Any ideas on what it could be and if I should be concerned???


Additional info:
* DEFINITELY not a bug bite
*she didn't get kicked
*not sure about the age because she is a rescue
*she also has a little hard thing on the back of her back right leg
just above the hoof (idk if its related or i'm just paranoid)

Pictures would be the best way for us to tell.

Ok i'll put one up tomorrow after school