As a Southerner its instinctive to save that bacon grease so I had a bunch of it in the freezer when we got our first pullets in September.
Edited by DenverBird - 2/18/11 at 9:48am
I started off mixing about a cup of bacon grease in with about a quart of feed to make my "winter warmth" mix. I then used this to supplement their feed on really cold days, putting about a quarter cup of the mix in their feeder - they were delighted to get it.
I then did some calculations. One cup of bacon grease has about 1800 calories (kcal). I figured out that mixing a quart of the "winter warmth" mix above with about 25 lbs of their feed comes out to about 20 calories per bird per day, assuming they're eating 2 lbs/wk. This translates to an additional caloric boost roughly the human equivalent of about 800 calories daily for a 200 lb person. I was giving them this as their regular feed during the deepest part of the winter. After I ran out of that mix, on some cold days, I'd come out and give them little pieces of pork fat trimmings. The reaction this gets is like throwing out free Snickers bars at a pep rally.
I'm not sure how an organic regimen has anything to do with whether the basic practice of supplementing feed with fat is bad for them. In my experience, its always best to have a high fat breakfast if you're spending the day outside in the cold. What I'm describing for my birds uses small-farm raised organic pork as the source of the bacon grease and fat trimmings; I use a strictly organic layer feed. If its important to you, that's what you've got in the kitchen, if its not important to you, then feed them conventional grease / trimmings if you want to supplement their feed with a good caloric boost on frigid mornings. About the only thing I'm really concerned about is what this may do the the cholesterol content of the eggs. But frankly I'm glad they're getting out in the run on cold days and not shivering in the coop. Check out the photo below and note the temperature on the thermometer.
Cutie, Patootie, and Dottie (two Barred Rocks and Wyandotte) hanging out in single-digit temps, Feb. 9, 2011, Denver.