Turns away
The Ghost has to leave Hamlet because morning is about to come. In Shakespearean times, it is believed that dead spirits cannot dwell during the daytime which is why they come during the evening. Since the cock crows, that means the sun is about to rise and The Ghost must leave.
The Messengers I think.
The rooster crows.
Yes. "It faded on the crowing of the cock."
Yes, crows have been observed to detect and react to the scent of death, which helps them locate potential sources of food.
Cats have high senses, yes they do detect ghost.
The Huckleberry Hound Show - 1958 Two Corny Crows The Ghost with the Most Baffled Bear 1-9 was released on: USA: 27 November 1958
Act crazy
Yes, dead crows can scare live crows. Crows are highly intelligent and social birds that often exhibit caution around potential threats. The sight of a dead crow may signal danger, prompting live crows to avoid the area or react with alarm calls to warn others. This behavior is part of their survival instincts, as they can associate the presence of a dead crow with possible predators or hazardous conditions.
Dogs usually bark at the entity{ghost}
"Gentlemen, rise. His highness is not well."
Not a dang thing. The ghost only talks to Hamlet; he will not talk to Horatio.