I've done it, in the attempt to make turkey moister. I had read about brineing, and besides it being utterly impossible in an italian kitchen with small space and only one bathtub and no source of ice cubes... i thought salt would leach out the juices inside. (You soak a swollen foot in salt water and it unswells)
Not sure of the science of that, i do remember a long discussion here once.
Having had turkey and chicken that other people think is good, and not liking it, i never know if it's going to come out the way I like it when people use a method like brining. I DON'T like any water outside the turkey, i do like the outside really crispy and the inside cooked through but juicy, so when you cut it liquid comes out. So i never trusted the brineing technique.
Anyway, i had hypodermic needles (they often prescribe medicine here in injection form and i learned to give them) and i made a salt and water solution and injected the turkey many times all over. It came out juicier than it used to.
But then i tried stuffing it (and chickens) under the skin with seasoned butter (pieces of butter rolled in marjoram and crushed black and pink peppercorns and crushed garlic) and roasted it and it came just as juicy, in fact, i think juicier.
I always roast on very high heat and it comes out juicier that way as well. The liquid doesn;t drip out, the hole is tiny, injection sized.
But try butter under the skin. wow. Not sure how it works, because the chicken doesn;t taste fatty (the fat eventually runs out) but maybe it helps the browning of the skin so it holds in the moisture better? anyway, it adds flavor too.