The run in the photo, my husband built to the same measurements as a run sold to accompany the one and only poultry house we have ever bought. All the others have been 'homemade'
It is recommended for 12 birds ! Although it is suggested that maybe it wouldn't be suitable to keep the hens housed in there permanently.
We have never used the run with the door closed, it serves purely as a shelter for the birds and their food. The only time it is used as a closed run is for young chicks.
The photo shows 7 of my hens feeding within the run, it horrifies me to think anyone would think it suitable for more than 3 birds and then only if moved on a daily basis.