She is about 15 yrs old she has been a great layer and mother for 12 straight yrs but last year all 12 of her eggs in 2 clutches were soft (leathery, thin)shells. All winter I gave her extra oyster shell and even ground it fine and mixed it with their food. They get turkey "grower" pellet, black oil sunflower seed, table scraps, pasta. Is she just too old now? I want to try a vitamin supplement. What do people give their laying fowl? I just read birds need calcium, phosphous, Vitamin D3 and sunlight. We hardly get any sunlight in Seattle and my peahen gets almost none. But I have a brooder light on 24 hrs a day. Is there a special UV bulb I should run?