I have a rental property with a lot of rocks and boulders on it, mainly in the backyard, in Chapel Hill, NC. The backyard is pretty large.  If it wasn't for the boulders, the land would be more usable.  What are options as far as removing them?  Has anyone ever done this before?  What was the cost?  

The rocks/boulders range from small ones of about a foot wide, which I can take care of, to the largest one which is sticking up about 7 feet above the ground and is pretty firmly planted in the ground.  Some are buried more than others.  Pics below.

Thanks.