My feeder is now in the chook shed and working well.
The only changes I made from yours was to swap the 45deg 90mm male/female fitting for a female/female to give a little more length because the feed was getting out of the end a bit when they fed. Luckily I didn't glue that one to make cleaning easier.
I also just used a blanking cap on the top instead of the screw top because it was easier and cheaper.