One bird is struck and killed by a helicopter in the beginning. A second bird, a pelican, flies into the oil rig during the explosion and has an extended sequence where it smashes into windows and equipment while panicked before dying on the floor.
Not directly squashed, but multiple heads are injured through sharp objects, falling debree, and blunt objects. One person hits their head while falling to their death.
There is only a few sudden effects in this film which may be startling
Total Jump Scare Count: 3 (3 Minor)
(Minor) (14:29) (Something flies into a Helicopter windscreen)
(Minor) (56:59) (A Bird suddenly flies through whilst a man is looking through his binoculars)
(Minor) (1:10:58) (Another Explosion suddenly goes off inside the ship)
Since it's based on a real-life tragedy and in the ending credits it shows the people who died in the event, I see it as a unhappy ending. The movie ends with many people dead, injured but also rescued. The main character survives and is reunited with his family.