My birds will consume them well when foraging but abundance varies greatly even before squirrels, jays and turkeys get their share. The chickens can choke down some sizable items but I am not sure they are able to discern which acorns are worth eating.
In a short-term pinch I will use a mixture of shelled-corn, oats, BOSS and millet as a maintenance diet, especially during the harshest part of winter when now growth, no egg production, and no molting. They are already eating more than typical so easily meeting their protein / exogenously...