You're lucky you made it a whole year! Boy, they can really put a dent in the feed, can't they? While I love my treadle feeders, I would point out that there are cheaper and easier alternatives. While I don't have any experience with them, the trigger/lever activated bucket feeders are well reviewed and can be
seen in this thread. Also see
post #10 & #13 in this thread for a very cleaver auto-feeder design. Of course, like a treadle feeder, the success of these types of feeders also depends on training the chickens to use them.
I'm about to go thermo-nuclear on the European House Sparrows in my yard. After returning home this weekend, I discovered that they had completely denuded my snow pea vines. Now they're trying to do the same with the cauliflower and broccoli plants. I built a diabolical sparrow trap last year, tested it and then released the captives after going a bit soft. I think they've finally pushed me over the edge now.