Moths in bird seed

Check the seeds for worms.
Some moth species lay their eggs in seeds. Have you heard of rice worm? Very common at wherever there is rice. They feed on rice, and they turn into moths after a while. If there was no worm when you got the seeds, the chance was the seeds had come with moth eggs. Since the eggs are small, you couldn't see them. Maybe you should keep the seeds in the fridge. Worms don't like cold temperature, even if it doesn't kill them it will make them "sleep".