ZIMSEC O Level Combined Science Notes: Poultry and Rabbit feeds


  • Food forms the major part of costs when rearing poultry for eggs and meat.
  • It is therefore vital that the poultry  feed is obtained, mixed and given to chickens in the most economic and cost saving way.
  • The range of feed and the composition of the diet depends on the breed and age of the chickens.
  • Day old chicks require fine mesh until they are able to eat large pieces of food e.g. seeds.
  • The feed should contain about 2% animal protein e.g. fish, meat, bone meal or blood meal.
  • This has all the amino acids needed by the animal for growth.
  • The carbohydrates part of the rations comes in the form of cereal grains e.g. ground maize.
  • The protein component is provided by soybeans.
  • Poultry birds also need minerals such as phosphorus and calcium for their eggs.
  • The feed may have limestone, meat or bone meal to supply this need.
  • Poultry birds also require Vitamin D in order to use the minerals inside the body.
  • Chickens should be allowed to roam free (be reared as free range/road runners) so as to obtain plenty of light (Vitamin D), green grass and cereal grains in addition to having balanced rations.
  • Such chickens (road runners/free range) provide good meat and eggs.


  • Rabbits require prepared pellets so that they can grow and develop into healthy large animals.
  • Farmers who raise rabbits on a commercial scale and for slaughter want them to grow quickly.
  • Rabbits need fresh green food but the pellets make sure that the food is balanced and contains enough protein for growth.
  • Young rabbits are weaned 4-6 weeks after birth.
  • They may be given 100g of pellets and hay daily for 8 weeks.
  • Working bucks (the males) continue to receive rations at this level.
  • Pregnant does( the females) should have 11g pellets per day plus hay.
  • The hay is gradually be reduced until  18 days after mating.
  • Then the does is left on pellets only until her litter is weaned.
  • Rabbits also require at least 1 litre of water per day and more if it is a female that is pregnant or suckling.
  • The efficiency of rabbits in converting feed into meat varies depending on the breed involved.
  • The average slaughter wight is about 2 kg which may be reached in 8 weeks in some breeds and 12 weeks in some breeds.

Composition of rabbit pellets

Rabbit pellet label. Image credit guineapigcages.com

Rabbit pellet label. Image credit guineapigcages.com

Ash (other minerals)12

Growth curves

Image credit uky.edu

Image credit uky.edu

  • The increase in body weight of chickens or rabbits can be used to produce a growth curve.
  • This curve shows the best time to slaughter the animals.
  • The slaughter time should be before the gain in body weight slows down.
  • Once the optimum slaughter time is exceeded the animals gain less and less weight per amount of food consumed.
  • This means that the animals will be inefficient in converting food to weight gain.
  • This is uneconomical and thus undesirable to farmers who want to maximize returns.
  • For broilers the slaughter time is usually 4-5 weeks.
  • For rabbits this is between 8-12 weeks depending on the breed involved.

The feed conversion ratio

  • This is the rate at which poultry birds convert food into bird weight.
  • The FCR is obtained by the formula below:
  • FCR=\dfrac{\text{food eaten}}{\text{increase in body mass}}

To access more topics go to the Combined Science Notes page.

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