Yes, it can. Despite the gore and horror of the zombies, the relationships between the characters are often heartwarming. There are times when they celebrate birthdays or holidays within the group, trying to hold on to some semblance of normal life. It gives a sense of humanity still existing in that harsh world.
Definitely. In 'The Walking Dead', there are many acts of heroism. People risk their lives to save others. Glenn, for instance, often put himself in danger to help the group. These heroic deeds add a positive aspect to the story. Also, new life is sometimes brought into the group, symbolizing hope and new beginnings, which all contribute to it being a feel - good story.