I had a conversation with the pet shop lady and asked her what the difference between timothy hay and normal hay was.. She said that the timothy hay had a sweetener added to make it more edible for bunnies and they should be given it mixed with normal hay as it increases the calcium levels to a very high state if used all the time... I have previously used it all the time and never noticed any problems but this came as a surprise to me .. Can anyone advise if this is true or not..