I've never dewormed either, but I found a round worm a couple weeks back. So they're all getting treated and I'll probably get a fecal done to check that it's under control.
I am the opposite. I wanted to individually dose each of my 30 odd chickens, cause I wanted to be sure they were getting the correct amount in the shortest time possible and I didn't want to have to confine them for a whole day, they love their free time.
I found a really effect method, for me...