Do you keep a shotgun close by for home defense? Many folks do, and I think the standard round for protecting your home against zombies is buck shot or slugs. Both of those rounds come with the stopping power to take down even the largest zombies, but have you considered bird shot? Yes, the cost savings is nice but the bigger issue is over penetration. If you live in place that shares walls with your neighbors (apartment, condo, town home, etc) or you have several people living under your roof, you should be concerned about over penetration. See, those rounds you are wildly firing at the zombies outside your door can cut through drywall like a hot knife through butter (because you always heat your knife before buttering your bread).
So the alternative would be to use bird shot because it won't be going through multiple layers of drywall or whatever your double wide walls are made of. Doves and quail are not nearly the same as a large zombie, but at close range the bird shot is still going to do some damage. Check out the vid below for more information.