Does one need to get rid of whole dagan (e.g. wheat or barley) kernels before Pesach (such as might be found in packages of birdseed)? Could there be any concern of a biblical/rabbinic prohibition?
If the kernels have never got damp, they will not have become chometz. OU Kosher has an article on “Tempering” (spraying grain kernels with water before they are milled).
The article states that
all tempered grain and any flour made from the grain are possibly Chometz Gamur.
Therefore, it seems that one would have to first find out that the grain had not been tempered and then would have to keep them away from any contact with water.
Birdseed likewise usually contains problematic grains. It is best to feed them with sprays of millet. Birds of the parrot family should be given sunflower seeds, as well as fruits and vegetables.
So, it seems that there would be a possibility of transgressing a Torah prohibition in possessing whole dagan kernels on Pesach .