Here is the link to my treadle feeder plans: https://www.backyardchickens.com/a/building-a-treadle-chicken-feeder I would also point you to two other types of auto-feeders that would work well at keeping sparrows at bay and would be much easier to make: https://www.backyardchickens.com/t/602082/for-those-using-lever-activated-bucket-feeders and post #10: https://www.backyardchickens.com/t/599511/does-anyone-use-rodent-resistent-feeders#post_7913179 Good luck!