Wudhu breaking with a drop of urine

Q:

  1. Someone told me that if only a drop of urine comes out you still have your wudu because a drop is less than a penny (coin), is this true?
  2. All impurity which is less than 3 to 5 centimetres in diameter is excused. I am sure two drops of urine on your clothes will not make a circle which is more than 3 centimetres, is that true?

Sucking blood

Q: I wanted to inquire about the drinking of flowing blood being haraam! If a person checks his sugar, pokes bimself for the blood to be released and
thereafter sucks the remaining blood from his finger, is this constituted as haraam?

Pigeon droppings in the Musjid

Q: I have seen scores of pigeons roosting in many Masjids.  They keep flying around and a lot of their droppings are found on the prayer mat, some dry and some fresh.  I had the opportunity to witness so much droppings continuously being made by the pigeons roosting in Jama Masjid in Delhi during my visit once, when I had gone to offer my Dhuhr Salaah with the Jamaath.

I require the following clarification.

1. Is our Salaah valid if offered at such a place full of pigeons' droppings, dry or fresh?

2. Do we have to clean only the spot of the droppings if they fall on our clothes if we are in a state of Wudhu or do we have to do our Wudhu all over
again?

3. Similarly, I have witnessed the same scenes at many Eidgahs in different cities during my travel, during Eid Salaah, where sheep/goat droppings/cattle dung are found all around dry or fresh, which the people responsible for the maintenance of the Eidgahs neglect to clean. Is our Salaah valid in such places?  

4. What is the Shariah Ruling on these kind of najis?