Over the past few months my one year old Welsh Harlequins have produced an occasional soft-shelled egg. Last week one died after being in distress for several days, despite the usual supportive treatment. I am concerned that this was egg peritonitis. My birds eat a standard 16% layer pellet free choice and have oyster shell available at all times. They free range in my large back yard every day, and forage for insects and other goodies. The yard is heavily planted with native plants and has a deep mulch, so there is a fair amount and variety of fresh duck food. What am I doing wrong? Thanks for any advice!