Millet is ok to ferment. Millet is NOT Milo. Millet is a teeny tiny seed that's cream colored to reddish. Milo is another small seed but probably at least ten times the size of millet. It usually is a reddish brown in color and very very hard to crack.
Thanks you guys....chickachee,
milo is grain sorghum, millet is a cereal grain (google)
you really don't need the huge regional menu of all the grains mentioned on this thread, not sure how many birds you are feeding, if only a few you can get wild bird seed mix it has a host of grains in it,,,if you have more than a few birds then using the local "scratch" feed should supply what you want
just my .02