I created a new world in 1.9, and after the update to 1.10 I noticed that my villagers won't farm either, they plant crops but nothing else. Also they seem incapable of breeding. I made a new world in 1.10.2 (creative) and built the same breeder both under and above ground and it works like a charm. A shame really since I've built a lot of things in my 1.9 world.
Oh and I'm playing in singel survival