I currently have chickens that I want to make a feeder like this for, but will be getting ducklings in June. I am wanting to make a feeder like this for the ducks when they are full grown: I've seen it recommended to use 4" elbows instead of the normally used 3" if roosters will be feeding, and smaller elbows for chicks. I was wondering if the 4" would be big enough for my Swedish Blue ducks when they are grown? I'm also getting turkeys and guineas...Would this idea work for them as well? Would the 4" elbow be enough for them?