I got the recipe from Lisa Steele's book Fresh Eggs Daily, but I changed the ingredients around to incorporate healthy herbs to naturally help my girls' immune system.
I spray a Bundt pan with cooking spray. Then I put a layer of frozen berries (blue,rasp,black,cran) whatever kind is available & you can find cheap. Next you will need 8 cups of seed,cracked corn, sunflower seeds, oats, dried mealworms or whatever kind of nuts/seeds your chickens enjoy. I also put in all the yummy herbs into the seed mixture. Next melt a cup of lard/suet & pour it into the herb/seed mixture & mix. Next pour 3 envelopes of Knox unflavored gelatin in a half cup of water; then pour it into 1 1/2 cups of boiling water. Pour that into the herb/seed/lard mixture & mix well. Finally pour that into the Bundt pan, press it down with a spoon, cover with foil & refrigerate over night. I only give them a slice a day & keep the rest covered in the fridge. They absolutely love it. It's also an amazing book filled with more recipes & goods herbs for your girls.