my local rental company has electric jack hammers. A lot of fence installers use them in my area due to all the shale. Goes through it like butter. They have 60 lbs electrics, and they also 60 or 90 lbs air powered. The electrics seem to be most popular and they are renting them for $50 a day. I don't know the brand name but you can search on Google and find em. Good luck!