Can you receive ultra balls from Pokestops?

After getting level 20 I was rewarded with 20 ultra balls (among other stuff). I assume this would have been like with the great balls, which unlocked them and allowed you to collect them from pokestops.

However after getting about 30-50 pokestops after hitting level 20, I have yet to get a single ultra ball, am I just incredibly unlucky?

Is it possible to get ultra balls from pokestops or is it going to be a pay to get item like lures and lucky eggs?

Yes, you can.

Source: I have. They aren't as common as regular balls. Don't forget to curve those when you run out of ultras.

Apparently you can. I just hit 20 after egg evolve strategy and I spin pokestop for the FIRST time and I get an ultra ball. I was very surprised and wanted to know how rare these actually are. So I know you CAN get them from pokestops but no idea about the chance. I wish I was this lucky with the egg hatches...

Yup, they definently do! They are a bit rare to drop though. Here are some screenshots from a lucky day:

Source