If you are interested in my feeders take a look at them.  I took a 16 ft by 60 inch horse panel, cut it into 8 equal sections (2ft x 60 inch) 2x4s and pressed wood. Make the frame with the 2x4s, a 2x4 down the center of the feeder box, wiggle the panels in from the sides, and 2x4 in the middle of the top to keep the panel in place.  Use  8 carriage bolts four on each end, where the legs attach to the frames, and the goats will not be able to demolish it.
Fished size 60 inches long, 3 ft high(you can make them up to 4 ft, but only the adults will be able to reach them) 24 inches wide.
I also made an awesome grain feeder....an old sink!!! plug the holes, and 2x4 frame around it. (its the yellow in the background)