Once slaughtered, the turkeys have to suffer one more indignity before arriving in your grocer's meat case. Because of their monotonous diet, their flesh is so bland that processors inject them with saline solution and vegetable oils, improving "mouthfeel" while at the same time increasing shelf life and adding weight.
The New York Times Op-Ed: About a Turkey. The author wants to persuade you to seek out a turkey which didn't suffer the indignities of a factory farm for your Thanksgiving meal, if only because it may actually taste like turkey. Regardless of your intent, the accompanying graphic alone is worth your click.