A few years ago we went to a family reunion down on the Navajo Reservation in Arizona. Not many trees there. We fell in love with their brush arbors.
We built one next to the greenhouse and are planning at least one or two more in the main chicken coop area. Nothing fancy - just some poles & cross supports with brush piled up on them - some are just lean-tos. We just used some arbor poles as the uprights (8'+ wooden poles for supporting grapes, etc.) and thick branches for the cross poles. Every spring as we trim suckers from the trees we throw the brush created on top of the structure. Every fall we clear it away before the first heavy snow (this year, we left it in place with no problems).
The simplicity and little/no cost appeals to us and the chickens love to lounge under it on hot days.