Hopefully I can explain this well . I've notice that all the coop bird entrance /exit doors be it large chicken coops or small stand alone duck pens are just holes cut to size in middle of pen so critters including wind etc can just blow straight in . Instead of this try making a wood "tunnel " type , length is variable entrance , keeps wind out & can deter larger predators . Used this all the time on our off ground Beagle pens . Make a wood tunnel bx slightly taller than exit door 3 long PCs top,side,bottom then cap on left or rt end & screw nail to wall . Bird walks up to frt of coop turns rt or left down tunnel to end then into pen. If on a above ground on legs duck/chicken pen put opening on rt or left side not in middle , depending on prevailing wind then attach tunnel . No snow/rain or direct wind can get in this way . I'll try do a pic . Luck
PS some training with feed & gentle persuasion may be necessary .
