If we want our characters' daily activities to bear some relation to reality, we're not going to be foraging by night!
That all depends on how you view foraging...
If you're in the complete wilderness, sure... foraging at night will be next to impossible.
But if you're near a ruined village or town, you can definitely forage through those ruins during night using a flashlight or other source of light.
And since I'm playing a campaign set in Sweden, there's not that many 10km² areas that don't have a village next to them (IRL, not on the *highly inaccurate* map that comes with the game... according to that one, Sweden is just wilderness).
EDIT: For example, right now my group has started building a base on an island right next to the town of Nora in Sweden. That's a town of around 6300 people in the year 2000. Sure, in my version of events, that town was the site of a large battle and most of it is in complete ruins. But even so, there should be enough edible conserved food for the players to find to last them for at least a while. And it should take the players more than an 8 hour shift to search through that 6km² area, so I'll be allowing them to search through it a certain number of times before each cumulative negative bonus to the roll.
That means that if they decide to send out the entire group (now up to 21 people) to search through the town in one go, they'll be getting negative modifiers really quickly (in fact, half the group will be hit with negative modifiers immediately), but if they instead send a few people to scavenge there once a day, it'll take longer.
Either way, that town will most likely (barring really bad rolls) give the group a week or so worth of food for the entire group.
Add to that the fact that they're on an island where there's plenty of fishing opportunities, they can hunt in the surrounding forests, they can start growing food (it's April in-game still), there's an Apple orchard on the island and so on, they should be on the brink of starvation, but won't have to move for the forseable future.
Also, I just noticed that all the cumulative negative effects are reset after a week in the rules (except fishing, which is reset after a day).