I've done a few
I did not want to have to rent any heavy equipment, generators or compressors to place mine.

I ended up using a hand held rotary hammer/hammer drill that just plugs in to a portable generator.
Bosch and Dewalt make specific Rock bits you can get online. home depot will not usually have what you need for bits

The 5/8" bits cut through solid rock like butter (good for re-bar)
The 1 1/2 " bits for the T-post work but its more work and I would not want to place a long fence using it.
I was placing my t-post in solid rock not just rocky ground. rocky ground would be much easier.

Going into solid rock took me about 5-10 minutes for each 1 1/2 inch hole and about 5 seconds for each 5/8" hole
for the 1 1/2 " holes I ended up making a 5/8" pilot hole then make the 1 1/2/" hole and that made it easier
If you have a dirt/rock mix then placing the 1 1/2 " holes would take just a few seconds.

I found that the 1 1/2" bits take a SDS max hammer drill not a regular SDS drill.
The 5/8" drill bits use a standard SDS hammer drill/rotary hammer


I ended up using the 5/8" for rebar to anchor down my feeders and also for most of the post for the feeder pens with just a few t-post. The rebar worked great for me in solid rock as post for the feeder pen. If you have a lot of dirt and rock mixed then I would stay with t-post.


If you have the equipment as shown above in the previous post, then that is the way to go for many t-post in a rocky/soil type ground.
But I have found the 5/8 rebar works really well if in solid rock

Let me know and I can send you a link to the drill bits I use.