Decisions on optimising broiler nutrient density - performance vs economic metrics

Excellent summary, Dr. Leeson, particularly for all of the industry to include independent poultry Growers and integrated broiler operations. The numerical values that you give are very valuable for our operations.

My experience is with integrated operations and another factor arises where the profit is calculated when the meat is sold to the grocery store. This factor is plant/packing costs that until the recent declines in ingredient prices were equivalent or higher than live production costs. With these Plant/packing costs, pounds through the plant are critical and an operation may elect higher feed/live costs to produce more pounds to sell. The market, in the US, is currently asking for more broiler meat production via higher prices. However, production is limited by the number of chicks produced and to some degree by the amount of live production broiler houses.

There are modeling programs that include these live and plant costs [Some are working on the price that various upscale finished products command]. When the modeling programs are adjusted to the production location's costs, the modelling programs are quite accurate in their predictions of performance, costs and returns.












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I would like to express my sincere appreciation to Prof.Leeson for the concise and highly valuable information. My question is this: Under conditions where the quality of feed ingredients is low(for example, very poor-quality soybean meal and similar issues), what is your recommendation regarding nutrient density?
Should we decrease nutrient density in such situations, or increase it? Thanks

There is another feed adjusment on daily feed consumption that the animal does each day. It is independent on feed formulation and embironmental conditions..
How do you feel and how much do you eat.

Dear Dr. Leeson, you have masterfully summarized what many of us have experienced in the industry regarding nutrient density. Thank you. Your figures regarding pellet size are very valuable, as are the estimates of net energy saved by going from 50% pellets in front of the birds to 90% pellets. Thank you very much, Dr. Leeson

Greetings and respect to the great Professor Steve Leeson
To balance the nutritional value matrix of feedstuffs in ration writing or the nutritional matrix. Due to the variability of the nutritional value of feedstuffs according to climatic conditions and soil composition or planting method. It is necessary to use feed for the bird according to the capacity of the digestive system and the time required for digestibility and absorption of nutrients in the feed based on dynamic growth. According to the genetic progress of the commercial strain. In addition to observing the principles of breeding in terms of complete temperature control inside the hall. It requires the knowledge and art of a poultry nutritionist. In the absence of these cases, digestive stress and changes in the bird's requirements and lack of proper performance for the appropriate weight in the consumer market. On the other hand, economic income, etc. should be considered.

Great discussion, Gentlemen, from many years (decades) following the field evolution, feed intake management was never assumed by the hunsbadry field team, and many aspects were sometimes delegated to the nutrition team.
Besides that, investment in all aspects has made evolution possible. Recently, considering the numbers from Prof. Leeson´s paper, people are feeding the birds, projecting a 1,35 F/C and ended with a 1,65 projections. Ok, birds are capable of adjusting even in their short lives.
Personally, I do not fully agree with the affirmation that ingredient quality is not related to nutritional density, considering the precision feeding and the great amount of antinutritional and allergenics in the feedstuffs, the pre-starter and starter that are always pushing the first step for great performance, deserve having better quality of feedstuffs and also great attention to the nutritional density, allowing to be a tool of growth curve management towards uniformity and lower costs.

There still seems to be considerable confusion about the concept of optimum dietary density and birds eating to meet their energy requirements or needs:
“The broiler still eats quite precisely to its energy needs and alters its feed intake in response to variable diet energy level.”
There is a classic graph in the 1974 paper by Colin Fisher and Brian Wilson, titled "Response to dietary energy concentration by growing chickens" (published in Energy requirements of poultry, British Poultry Sci. Ltd.). It clearly shows that broilers do not precisely adapt consumption to energy level. Yes, consumption decreases with increasing energy level, but not in precise indirect proportion, and the birds get fatter. The last of the coffin nails for the theory of eating to meet energy needs or requirements should have been driven in by the papers of Jackson, Summers and Leeson (https://doi.org/10.3382/ps.0612224) and Pesti (https://doi.org/10.1080/00071668308416717), both published in 1982.
The correct interpretation of those papers is to feed nutrient levels that maximize profits. It was shown by Pesti, Arraes and Miller (https://doi.org/10.3382/ps.0651040) and many others. It was recently shown again in the Ross Broiler Nutrition Supplement 2025 https://aviagen.com/assets/Tech_Center/Ross_Broiler/Aviagen_Ross_BroilerNutritionSupplement.pdf. It contains a graph showing how amino acid levels should be determined on an economic basis; And the profit maximizing levels are different depending on whether live birds or portioned birds are sold. That is because carcass yields are variable depending on dietary amino acid levels. And the best level will change with input and output prices. Some confusion may be introduced by this graph since the y-axis is labeled Cost/Income. It should be Cost or Income so that profits are maximized with the maximum Income minus Costs (distance between the lines in the figure). Therefore, “Since feed intake is predictably influenced by diet energy level, all other nutrients and especially the EAAs, are adjusted to “normalise” their daily intake” should also be put to rest. There is no normalized level of EAAs independent of prices. The EAA levels to maximize profits should be the normal, as shown in the Ross Supplement graph.
The situation is entirely different for commercial laying hens. Their energy intake can be predicted very well by equations such as MEI = W0.75 (173 – 1.95T) + 5.5 ?W + 2.07 EO), where MEI = metabolizable energy intake (kcal / day), T = Environmental Temperature (oC), W = Body weight (g), ?W = Body Weight Gain (g / day), EO = Egg mass output (g / day); from the NRC (1994). And notice that there is no “thermoneutral zone”. Hens must heat their bodies from ambient environmental temperature to body temperature and are always following the normal laws of physics. Hens lose heat to their environment if they are warmer than it, hence efficiency is increased with increasing temperature (if egg output is maintained). Hens do adjust their consumption to match output quite nicely because it is very difficult to change their body composition. Energy levels for hen feeds should also be chosen to match profit maximizing levels. And how much feed, energy and other nutrients they will consume depends on environmental temperature, just like broilers.
The same Colin Fisher mentioned above wrote a very nice introduction to the intracacies of choosing energy and nutrient levels for poultry in: “An overview of poultry models” [in Nutritional Modelling for Pigs and Poultry [Sakomura NKG, Gous RM, Kyriazaki I, Hauschild L , editors]. Wallingford, Boston: CABI (2015). The entire book is a very good read. Models help put everything in perspective and present a framework to deal with changes in animal and plant genetics, processisng methods and changing economic conditions. Broilers should eat precisely what producers need them to eat for maximum profits, subject to societal expectations.