The crow is a dangerous animal where t-Virus
and other types of outbreaks occurred as they tended to consume infected flesh and become carriers. When a crow becomes infected themselves they don't display many typical physical changes associated with the virus - but their aggression is markedly increased as well as their strength; particularly their pecking power.
At best an uninfected crow is capable of causing small injuries such as cuts and bruises, but a t-Virus
infected crow is capable of killing an otherwise fit and healthy human being. In particular those encounters at the Spencer Mansion
tended to attack in large groups, smashing through glass as if it were paper and attacking their target.
In other cases regular crows were observed consuming dead bodies in the where parasitic Plaga
had taken over. They did not seem to be afflicted with the parasite however, but they did carry objects on them such as money or even hand grenades or boxes of handgun ammunition which they must have taken a liking to and stole.
Finally, crows also were present in Dulvey, Louisiana - seemingly unaffected by the Mold in the area. However one met an unfortunate end as it was found to have been cooked alive in the microwave of the Baker family's guest house. It's unlikely this was done for food - most likely for a sick joke.