Been around chickens quite a lot, and around cows a bit. Chickens don’t produce nearly as much methane as cows, chicken manure is an excellent fertilizer, arguably even higher quality and lower footprint than cow, their food consumption even per unit of mass is quite small, they don’t take much space, and overall, they’re relatively easy to work with.
That said, plant-based options are even better in that respect.
No, but I have experience spending my entire childhood on the countryside. Smaller scale, same idea.