I'd add a lid to that feeder, helps with both birds and mice (and maybe chicks) getting into the top. Metal, or a piece of wood cut to fit.
We too have a few mice, and house sparrows, getting into the coop when the door is opened. Miserable little beasts!
Sheet vinyl strips hanging at the...
Having two or more feeders and waterers helps keep the flock social order calmer, so everyone can eat without being harassed.
My metal feeders have lasted way over ten years, indoors out of the rain. Also, Premier1supplies sells good plastic feeders, with deeper troughs that help limit billing...