Cut sisal string into four, 12-inch pieces.
Fold each piece of string in half and tie an overhand knot to make the string into a loop.
Melt lard or suet in a large pot on low heat. Keep an eye on it as it melts, and stir frequently. Melting times will vary, usually between three and five minutes. Transfer the lard or suet into a large mixing bowl after it is melted.
Stir in the peanut butter, flour, corn meal and seeds.
Divide the mixture into four equal portions.
Form the mixture into a ball around the knotted end of the sisal string so the knot falls roughly in the middle of the ball.
Place seed balls in the refrigerator overnight.