Pink or frothy blood usually means a lung hit. Dark blood can mean a liver hit,look for bile or stomach contents in any blood. My 16 yr old son shot his first deer sunday morning with a bow. He came back to the cabin and told me he needed some help finding one. When we went to where he shot it it was bleeding out both sides very dark blood. I knew he had hit the liver. The arrow was drenched in dark blood with no bile or stomach contents on it. The blood trail ran out in 100 yards so 4 of us started down this draw 50 yards apart looking. We found the doe piled up in a thicket 500 yards from where he shot her. He hit her forward in the liver, but missed the lungs. Its a deadly shot but they will run a ways before dieing.