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.

I don't know what a sanitizing chicken is, and apparently neither does Google. I assume from context it means chickens bred to lay eggs?

In this case it's chickens which get carted around a few days behind the cows. Cows eat grass. Cows poop on field. Flies lay eggs in poop. Eggs hatch into maggots, which eat poop. Chickens dig through poop looking for maggots. This spreads the poop out and gives the chickens an excellent source of protein.

Cow poop is actually a good fertilizer for grass, but it's too concentrated normally. The chickens spread it out to a more reasonable concentration and produce eggs in the process.

How are they farming the chickens? Free range, or in broiler barns?

I'm not going to rewatch it, but the facility they visited used uncaged chickens housed in a barn. If you're making a point about the ethics of it, note that even the concepts of "intensive farming" and "humane treatment of animals" aren't mutually exclusive.

Agreed. But broiler barns and cows in fields isn't a fair comparison.