Hi, My birds keep hanging round the salt bin on the side of the street (The yellow ones which contain salt for gritting roads) eating the spilt salt I have tried different types of grits, minerals,pick blocks, matrix over the last couple of years Yet my birds are still returning to salt bin Two questions What are they missing from their diet to keep going for salt And Is this constant intake of the road salt doing any harm to my birds Thanks in advance for your feed back Very much appreciated