have been layed low,for the past week, with the cold and flu,birds just getting fed and watered,today feeling a lot better,decided to let some out and clean their section out,came out the loft,when one landed on the house roof,gave a jump when it landed, and rolled down the roof,on to the conservetry roof stone dead,not a mark on it,no broken bones,was a 9yr old hen,i am thinking heart attack,what do u think,