I was thinking about how downright pathetic and unable to stand up for herself Cally was in Doomsday, which was weird given the writer/director's love for the Action Girl trope. It eventually hit me after reading about the main character's background - Cally was supposed to be the contrast to Eden Sinclair. Eden grew up on the streets and learned to be tough and hold her own, so now she's a super tough Action Girl. Cally would have grown up with her abusive and psychotic father and brother without a chance of holding her own, so she learned to be afraid of them and stay away from violence. -Whatever
More Fridge Logic than anything. Why didn't the cannibals eat the cows outside of the city? You know instead of people.
Possibly they did. They just ate people as well, for the hell of it.
Also there were that many cows after 20 odd years of barely anyone around, not as the virus swept in.
Granted, but cows are a much better source of meat than people ever could be... it takes a human being 15-20 years to grow to a 150-200 pound state, it takes a cow maybe 9 months to grow to 550 pounds or more. You'd think if cows were a few hours travel away, humans wouldn't be quite such a delicacy.
Perhaps they had yet to notice the cows?
Another piece of Fridge Logic: Why were people surprised at survivors in Scotland? Even without immunity it's clearly not an airbourne virus and there is a lot of Scotland with next to no-one living in it that would remain isolated from infection. A few survivors were inevitable.
Not to mention, lots and lots of people would have sealed themselves in with some food and water at the news of a major virus outbreak that was transmitted by touch/blood/whatever. It's established in the intro that it took at least a couple months from first infection to where they were rioting and building a wall. How would you not plan for survivors who simply avoided contact?