Can't say I've noticed. Try marinating the meat first? Let it sit in some lemon juice or white wine vinegar for a few hours beforehand, this will tenderise it as well as giving it an authentic tang. With chicken, try thigh and/or leg rather than breast - much more moist and more flavour - better still, leave them on the bone, this will make them even more tender and flavourful.
Of course, if you did all that and it was still dry, I don't know what else to suggest!