genetic engineering

this one is not form a text book but from a class a friend of mine took years back. the class was Bio-Ethics and Society, taught by a genetics prof and a philosophy prof on the ethics of genetic engineering and other touchy scientific issues.

chickens have a nesting instinct, such that when they are kept in small enclosures like the kind egg farms use, without any nesting materials, they stress out and start plucking their own feathers to use for nesting. what if the gene for this behavior was found and could be switched off? (assume no adverse effects from such an alteration) the chickens would be less stressed in their small enclosures, there would be no extra cost for the egg farmers, and they wouldn't pluck out their feathers and be naked just to have something like a nest. should the gene be deactivated?

i would say yes, as this alteration would decrease the suffering of these animals and maybe they would produce more or better eggs when they're not stressed. also i imagine it would get cold to be a naked chicken. the argument against doing something like this is that it makes the chickens less chicken-like. or that genetic engineering is a bad idea in general.

the arguments against genetic engineering are usually something along the lines of "playing god" is a bad idea, and we could create a monster. a more legitimate claim in my opinion is that we don't necessarily know all the effects of turning on/off a gene or adding a gene from a separate species. as far as "playing god" goes, genetic engineering has been going on since we stopped being hunter-gatherers and started farming. selective breeding has given us large bananas without seeds, seedless grapes, wheat and barley with bigger and tastier grain, not to mention several domesticated animal species. creating a monster is still possible, but we don't need genetic engineering at the DNA level to do it. Caulerpa taxifolia is an algae that was selectively bred to thrive in aquariums, especially non-heated ones. it was accidentally released into the Mediterranean sea in 1984, and the cold-adapted algae thrived, to the point of choking native vegetation. the invasive species has since been found off the coast of California, and New South Whales, Australia. there are extensive measures taken to control the spread of the algae, but little can be done once it gets a foothold. this is certainly a man-made "monster" ecologically, and we are responsible for its behavior. but invasive and/or destructive species such as this have evolved naturally. so should a naturally occurring organism be controlled? plague is natural, should we be saving the prairie dogs from it? is this algae just special because we created it? where do we draw the line?