hay feeders

Right now I have three goats, but we are planning to have a lot more in the future. Does anyone have hay feeder ideas that aren't too expensive that will work for a lot of goats?

Getting our first NDs in the spring... Anyone know of a place that sells or have plans to make an outdoor hay feeder - I need one with cover since it will be outside in the elements...? What do you guys use outside? Thanks!