Hopefully this is the right Forum to ask this. Normally when I boil eggs I add some baking soda to the water. Is it safe to feed those shells to my chickens? Does it take away the calcium in the shells? Thanks!
A chemical reaction hasn't occurred which changes the shell. Whatever is left on is surface material.
You'd probably be fine without rinsing. A little baking soda won't hurt the birds. It is an ingredient in home-made electrolyte solution for chickens during hot weather.