Hi -just joined, live in Somerset UK, have had 3 chickens for just over a year- all 3 laid brilliantly for a year snd now 2 have stopped or just lay soft shell eggs, for several weeks now. lve tried extra oyster shell, grit and a tonic to no avail. they are cept in a lsrgish run and free range in the garden for a couple of hours each day. ( read that I should cull them -that isn, t going to happen! any suggestions please?