If this is being done to de-frost it, then yes, because this kind of rapid de-forsting re-activiates bacteria in the meat which can give the consumer food poisoning.
Ideally, cold water should be used to rinse food - hot water is drawn from a tank which can contain microbes and germs which may transfer to the meat with results as above.
Yes. Unless it was over 80 degeres C - which is very unlikely.
It wouldn't be dangerous if you were just washing it and then you immediately either cooked it, or cooled it down again. It you left it at room temperature then the warm water would have encouraged a flood of bacteria on it.
And as a-h says, hot water is nowhere near as hygienic as cold.
All that said, people seem to be obsessed with over-the-top hygiene precautions now. Our ancestors managed to survive far worse things than washed chicken.
Yes water stored in the hot tank can harbour germs which would potentially be transferred to the chicken. You wouldn't drink from the hot tap and neither should you prepare food with water from it. Water should be freshly drawn cold water or boiled waterm and nothing else when dealing with food
The main danger from this is that you are spreading the bacteria over a larger are, around the sink area, etc. and can therefore cause cross contamination.Remeber raw foods are not a high risk as they are to be cooked and most of the bacteria will be killed. Cooked foods are a high risk as they require no further cooking and should be stored at the safe temperatures.
What if the hot water is heated by a Combi-boiler? In this instance there would not be any water stored in a tank as the water comes directly from the mains and only becomes hot after passing through the boiler system.