Resource Guarding
Mild resource guarding is extremely common among newly arrived foster dogs. The first sign is that the dog hunches over his prized possession, lowering his head and forequarters to the ground as if protecting its guarded object with his own body. He may give an approaching interloper a sidelong glance without moving his head, showing the whites of his eyes in a phenomenon dubbed "whale eye" by Sue Sternberg. If tested further, he may growl, snap, or even bite seriously.
Resource guarding most commonly manifests over a high-value chew, food bowl, or favorite toy, although some dogs also exhibit it around doorways, thresholds, sleeping places, and proximity to the owner. It's common among newly arrived fosters for two reasons: (1) most of these dogs have gone seriously hungry in the past and haven't had many (or any) toys of their own, and they don't understand that they've just won the jackpot in life and will now have plenty of nice things, so they guard their prizes ferociously; and (2) they don't have any real relationship with you or other people and pets in the household yet, so they're not as forgiving of intrusions because they have no reason to believe that you can be trusted that far.
Luckily, mild resource guarding is usually fairly simple to nip in the bud. Once again, management is key. Feed your new foster dog all his meals in the crate and only allow him to have high-value chews when he's being crated for bed or while you go out. This is advisable anyway because it prevents him from being interrupted by other dogs or small children while eating and builds pleasant associations with being in the crate; that it happens to be the best preventative for resource guarding is just a happy accident.
Crating the dog during meals and while he's enjoying chews accomplishes two things. First, it reduces the risk that someone will accidentally provoke the dog into snapping or biting when he's guarding one of his treasures. Second, it does not give the dog an opportunity to practice his misbehavior and develop it into a habit. If the foster dog learns that growling makes people back away from the things he wants, he has an incentive to growl more often and start guarding more objects.
