I built one! first I tried 45 degree angles, since my chickens are only about 8 weeks old and I was worried about how far they would have to reach with the 90 degree ones. The 45's made it too easy to shove the feed right out onto the ground! so I went back for 90's. first the one and only duckling (he's almost 2 weeks old) figured out how to use it in under 10 seconds. most of the chickens just gave it the eyeball and walked away, but the little cross-beaked runtly one climbed INSIDE the 3 inch pipe. maybe it's the first time she's been able to get her head right into the food. I'm hoping it's a deeper dish and she will be able to eat a little... but i'm going to have to add another elbow, because when she's in there with her entire tiny body no one else can eat. While she'll stick her tiny head into the 2 inch pipe, and the duckling will, the older guys are enough bigger I think it feels like a bit of a squeeze to them to put their heads in it. But she can't reach to the bottom of a 2 inch 90 degree pipe... so we'll have to get 2 of the 3 inch openings going.
for a total of 6 chickens right now this seems like the perfect way to keep my chick crumbles from being scattered all over the yard, let the runtly one get her face right in the food without it being thrown around, and keep it a bit more dry if it starts to storm.
Hooray! a feeder that can't be pooped into, rained into, and will discourage wild creatures from coming into the yard because feed won't be dropped all over.
since I built the chicken house out of all scrap material I figured i could spend a bit on the feeder & waterer... so I did get all new buckets & pipe. If I had those flat-sided cat litter buckets I would have tried that, but my stack of 'already-owned' buckets was all from driveway patch so I didn't feel comfortable with all the petroleum product as feed & water supply stuff...it's fine for moving dirt and stuff, but not to eat out of!
Oh -- I did use a 2 1/2 inch holesaw for the 2 inch pipe, and a 3 3/4 inch hole saw for the 3 inch pipe. I used white duct tape on the inside to secure things to see how it worked, and may switch to silicone at a later time once I'm satisfied with placement. the holes were a touch large to hold the pipe on their own, but that was the size holesaws we already had and I didn't want to buy more tools just for one project. using the 'street' pipes was great because the cuff I sawed off the bottom fit onto the outside of the pipe, preventing it from slipping back inside and providing protection from elements and spilling feed. I just used the tape to secure the inside part to the bucket.