Hi MyHaven ... the baking of shells I found on another thread here - American. So maybe they have to do it more than we might for various reasons. AND I guess it would depend on how quickly you clean / wash out the inside of the shell, and then crush it up. I have never given my girls any of their own shells - but another lass here had a brilliant idea - hard boil the whole egg, mash it ALL up, so's it looks nothing like anything the chickens would recognise, and all possibilities are covered. Plus they get the goodness of hard boiled whole egg. I am going to do that myself. Great for protein too. Which brings me to my experience with my one Barnevelder ( in response to your question ). She laid beautifully during the summer and early autumn, and then suddenly stopped. She is very pale combed compared to the other two who are still laying, but she's happy enough it seems ... although very quiet compared to what she used to be. It is Winter of course, and I have noticed she is definitely moulting, but not quite as much as my Araucana. I rather think she might be deplete in protein, so I give her a once weekly small plate of cooked mince or a bone to pick on ( by herself so the other gormandisers don't get it ) ... plus some grated cheese - but they all get that. She eats well, is interested enough in everything going on - but sets herself apart from the two laying chooks. She perches by herself too. I am waiting to see what Spring brings with Milly Barnevelder. She is a size between Bantam and Standard. She seeks sunlight whenever possible and sun-bathes. The others don't bother. My little Araucana is moulting heavily, is not eating as much as she did ( which is apparently normal during moult ), but otherwise is in great and active fettle. Good luck with your Barnevelders - they are beautiful chickens. l Cheers .....