Clearing Space for Coop

I have an area which is overgrown with bramble/briars and stinging nettles that im eventually converting to a coop/chicken run. I'm wondering if I can set up a small chicken tractor and run to begin with and will the 3 or 4 chickens clear this area over time or do I need to get busy clearing it first myself.

Will be my first time owning chickens myself so any advice be greatly appreciated.

Ireland 🇮🇪