I have been playing on a vanilla 1.16.5 server with my friend, and one of our recent projects had been a villager breeder. We had followed LogicalGeekBoy's villager breeder design with one major problem; the farmer villager would not plant any crops of his own anywhere in the 9x9 square.
I have tried a few things such as:
MobGriefing being set to true
Placing the breeder well outside of a village (over 200 blocks away)
Making sure the area is lit up enough
Breeding the villagers hasn't been a problem though, when given enough carrots they happily breed with each other and the system works fine, I am primarily struggling with getting the villagers to be self sustainable and plant their own food to breed.
Thanks for the reply, but I just figured out that the problem was caused by my own stupidity. While testing a previous farm I had the 'doDaylightCycle' gamerule set to false, with the time stuck at around 500.
Obviously this meant the villager never got to his working hours of the day, which explains why he wasn't doing anything job related.
Issue is fully solved now and everything is working great