It's large compared to the average, but the longer we've had chickens the more we're convinced they thrive better when given appropriate space (anecdata about average age of our chickens vs all other people with chickens we know), leading me to think something like yours is still too small even for 2 chickens.
For us the minimum is now such that there's at least some of the gras/moss left throughout the year instead of the puddle of mud we used to get. Plus I'm not gonne lie: seeing their (and their ancestors) behavior 'in the wild' it feels morally/ethically better as well. Especially the younger ones are keen explorers: easy to see when let ranging free - they'll go in a radius of like 100m around their nest, but not much further than that. Apart from that one mandatory weirdo obviously.