In the last week both of DS2's nails on his big toes have had the top layer peel off. It first looked like the whole nail was going to go but there is a thin layer left behind attached to the skin so it isn't hurting him. Tonight his little toe also lost the top layer.

Do you think this could be due to a lack of calcium or is it just that his toes are getting damaged as he crawls/climbs/walks etc? (he is 16mths)

He usually has milk with cereal in the morning, cheese on a sandwich at lunch or as a part of afternoon tea, often has yoghurt for dessert and has about 160mL of milk before bed.

His brother had a similar thing about a month ago with one of his fingernails. It cracked really low down and then grew out slowly before snapping off.