Should Labs Have Toys?

This was the subject line on an email I received today. Being a thoroughly doggie person, my immediate mental response was something along the lines of "What? Who in their right mind would be against giving their Lab a toy?" But when I looked a little more closely and saw that this email was from Science magazine, it became a little clearer. We're talking laboratories here, not Labrador Retrievers.
Still, it raises a thorny question. In recent years, laboratory animals have been living improved lives due to environmental improvements. Mice have nesting materials and objects to graw and sometimes even outright toys. But now the question is rearing its head -- is this variability on enrichment details between labs leading to confounding results in research?
This is another tough one, akin to the Supreme Court case of free speech versus banning video depictions of dog fighting (which is now being heard, by the way -- and the justices seemed disinclined to abrogate free speech on this subject). Of course laboratory animals should be treated kindly and given ways to comfort and entertain themselves. . . but. . . they still are laboratory animals, and the reliablity of results obtained from their use is vitally important.
So what's the answer? Maybe there need to be specific guidelines for all labs to follow, so that all lab mice receive the exact same environmental enrichment. That would seem to be a simple answer.
And how does this relate to dogs? Well, as I've mentioned before, dogs are now often serving as research subjects because they naturally are afflicted with many of the same diseases as humans. And that research is made even more applicable because dogs share our environments, in all their variations. So the really far-out response to the question of enrichment for lab animals may be to make them non-lab animals, and place them in the homes of researchers as if they were pets. I realize that this is hightly impractical, as the numbers of mice in research are still astonishingly high. And I suggest it with a heavy dose of sarcasm. But in the constant balancing act of research versus animal welfare, thinking outside the box rarely hurts.