I've come to the opinion that most
chicken tractors are only appropriate for about two
chickens. Just too small for many
chickens for more than about 4-8 hours in any one location. Any of the bigger ones are also going to be limited to the locations they can move through in a small landscape.
I now use mobile perches and mobile nest boxes that I can move around and I use the easily movable plastic fencing and step in stakes to give the chickens larger areas of
yard so I don't have to be around to move the "
tractor" several times a day.
Now I might sing a different tune when/if we start having troubles with predators but I have a feeling my choice then will be to see about getting a dog that would protect the birds but I haven't done much research on that yet.