The bird seed growing areas in eastern Australia have been badly affected by drought for the past two years. Stocks of seed are low and good quality seed is hard to get. Always test your seed when you purchase it to determine the germination percentage. Old seed of poor germination ability is obviously not as nutritious as freshly grown new seed and if you are using the old seed in a sprouting mix it will send the sprouting mixture rancid and can be harmful to the birds.
To test the seed use a plastic takeaway container with lid; place one layer of kitchen paper on the bottom of the container; saturate with water; place a layer of sample seed you wish to test; cover with another layer of kitchen paper; drain off excess water; place the lid on and place in a warm position. Some sign of sprouting will be evident within 24 hours and by 48 hours should be enough time to confirm whether seed is viable or not.
I suggest you buy a small amount of seed and take it home and test it and if it is no good go elsewhere. Good luck but do not buy rubbish.