Cattle have a FCR of between 5 and 20 or so. Chickens more like 2ish. If beef is bad because it takes 20 units of food to make one unit of beef and you have a way to make 4x the units of food per acre, then your effective FCR (relative to traditional methods) drops from 20 (at the worst) to 5. If it was at 5 then your effective FCR could be as low as 1.25 If it was more in the middle at say 10ish then the effective FCR could be at 2.5 which is pretty respectable. This is made better because you're also getting eggs from the sanitizing chickens and meat from the broiling chickens that are all making multiple passes over the same land at different times.

This is of course predicated on grass fed beef with the farmer taking a substantial interest in raising as much grass as possible (sanitizing chickens and paddock system). It's not a lot of work, but it does take more effort than just throwing grain at cows in a feedlot.