This is an edited version of Automatic Chickenfarm by iOser100. The original schematic was done by Trippel2511. See that one here: https://www.minecraft-schematics.com/schematic/12066/
There were some problems with this original design, that being there was loss of items to the lava. This is fixed by using a hopper minecart just below the slab that the baby chickens stand on. You can still use the original design with just a hopper, but you may lose quite a bit of items to the lava. This is because the hopper minecart will pick up items faster than a hopper alone.
I also did not like that the farm was surrounded by solid blocks and couldn't see into the farm. I changed this to white stained glass, but you can change those glass blocks to anything (solid or transparent). Only the stone and cyan concrete must stay as solid blocks due to the redstone.
This farm works by having adult chickens standing above hoppers laying eggs into a dispenser that will shoot out eggs onto a slab producing baby chickens. The baby chickens are just short enough to avoid being killed by the lava. When they turn into adults, they hit the lava and die, producing cooked chicken and feathers.
You will also need a hopper minecart in this design (it is not included in the material list since it counts as an entity but will appear on the schematic)
If you are building this in survival, here is a complete list of all required raw materials:
Total iron needed: 33
Total redstone needed: 10
Total wood logs needed: 18
1 bucket of lava
1 slab (any type)
33 building blocks (any type)
10 building blocks (must be solid)
Thanks and enjoy!