You could use bacon grease if I'm thinking right. Just cook bacon, gently pour the grease into a jar with warm water and then allow to cool. You'll have hard bacon fat floating on the top. The water helps you to remove it from the container and it helps because the meat will sink to the bottom. Otherwise, buy fat/tallow from the butcher (or get it from a friend, whatever), slice or chunk it and cook it like you would bacon, and again, drain it like the bacon. Then, you can melt it again (put the solid fat in a jar, put the jar in a pot of hot water and heat the water until the fat melts) and mix it and bird seed together and put it into a mold. You could use those little tupperware containers, a suet shrink wrap thing from the packaging, or you could put it into a cake pan and just cut it into squares.