I haven't been on BYC for many months, but wanted to give this update--
I got frustrated with making the bird blocks, especially with using birdseed--the millet is a PITA. I've started making them again using my own scratch mix which has corn, wheat, sunflower seed, dried peas, and oat groats, and this mixture is a LOT easier to work with (with the unflavored gelatin). I've been making them in a muffin tin, but I think I'm going to upsize them. No need to bake anything, just let them set up and dry out.
If you make these, you HAVE to try one of those hanging bird feeders, it is just too funny to watch them. (You can also buy the seed bells and just hang them, make them jump a little. One of mine hangs over a roost, so the chicken on the roost pecks at it, and the others scurry around underneath looking for anything that drops off. It keeps them busy for hours, and great entertainment for humans also.