Fattening up chickens is a process in which you change or add onto your bird's diet in order to plump them up, for either meat or egg purposes. There are a number of different ways you can fatten up your chickens, but however you go about it, fattening up a chicken will most likely yield disappointing results if the birds don't have a good amount of flesh on them already. Because flesh is grown during the summer months, it's important to feed your chickens properly during this time before fattening them up during winter.
Mix together your collection of grains and put the mixture through your grain grinder. Good fattening mixtures consist of two parts oats, two parts buckwheat and one part corn; equal parts of oats, barley and buckwheat; or two parts barley, two parts low-grade flour and one part wheat-bran.
Mix the ground-up grains with sour skim milk or buttermilk, 15 to 17 lbs. per 10 lbs. of grain.
Pour the mash into the feeding trough and provide plenty of water along with each feeding. Feed the chickens lightly for the first week three times a day, giving them less meal than they would consume entirely, thus leaving them slightly hungry in preparation for the following weeks.
Clean and turn over the troughs when the chickens have finished feeding. After the first week, feed the birds twice a day as much food as they can eat.
Supply your chickens with ample amounts of water at least twice a day.