For a chicken coop me thinks this is being overthought a bit here. Dig holes-place posts- pour dry sackkrete and add a bit more water. Stand back and wait a few hours and try to get that post out of the ground.

Last edited by Filaman; 05/30/20.
What goes up must come down, what goes around comes around, there's no free lunch. Trump's comin' back, get over it!