Firstly, stock yer ship's hold with a handsome cargo o' pellets. Be ye one o' those who think seed the best diet for a bird? Heave to, ye poxy dog! Seed be high in fat an' low in nutrition. An' don't give her salt or cow's milk or foods high in sugar. Wean a bird on this witches' brew an' ye be consignin' it to Davy Jones' locker before the poor bastard's time.
I have found it helpful to do the stretching exercises my physical therapist recommends. Do some core strengthening exercises, such as the ones highlighted at The Mayo Clinic. By keeping your core strong, your back won't put itself in a position to cause that sciatica pain you are having.