Poultry feed production
December 01, 2005
by Melissa Alexander
Ideas for improving the feed-making process
by Jonathan Bradshaw
Producing poultry feed involves the same basic principles as those that apply to producing other classes of animal feeds: in order to produce poultry feed effectively, you must process the largest possible volume in the shortest possible time at the lowest possible cost.
While this is an elementary concept, it is worth examining some of the less obvious ways to achieve this basic goal.
In the 21st century, the mills that tend to run most efficiently are "single species" facilities. The risks of cross-contamination have forced those producing feed for more than one species in the same plant to evaluate their operations and segregate their facilities. At the very least, their blending and pelleting systems are separate, even if the intake of bulk raw materials may be carried out jointly to a small extent.
Producing poultry feed in large volumes is a prerequisite of an efficient mill. Most major producers are now fully integrated, with cereals and vegetable proteins being sourced and bought at the same time that processed poultry is sold to the end user, often several months in advance.
This degree of integration allows the mill manager to optimize his mill operation and use his vehicle delivery fleet to maximum effect. Proper analysis of operations is essential to see where continual improvements can be made. The use of outsourced specialists is vital to ensure that mill managers and transport operators do not miss glaringly obvious opportunities to make improvements.
A well-organized order reception system allows for proper planning of raw material deliveries to the mill and for the most effective production runs to be achieved. Minimizing die changes, medication switches, cleanouts and runoffs are the lifeblood of the production schedulers. Production planning is a task that often falls to the mill manager and sometimes does not get the attention it deserves.
With judicious planning of delivery times and transport routes, the optimum throughput of feed through the outloading system can be achieved. There is no value in carrying fresh air on delivery vehicles. It always must be the aim to have the maximum vehicle payload possible. Scheduling deliveries through the night and running vehicles on a shift basis assists with reducing costs.
CONTINUOUS RUNNING EFFICIENCIES
Again, it is obvious that mills running at the maximum throughput for the longest time will spread their costs most effectively and consequently operate at the lowest possible unit costs. Running 24 hours a day, seven days a week, with shutdowns for maintenance every eight weeks or so, is the most effective way to operate mills.
Milling staffs enjoy the freedom this type of working arrangement gives them by allowing them to work in concentrated time periods and giving them a reasonable amount of time away from the mill to pursue other activities. In order to achieve this type of operation, it is often necessary to examine the onfarm storage facilities and provide farm bins, at or below cost, which can often achieve savings that would have not been possible.
There are a few aspects of continuous running that require comment. For example, boilers that provide process steam always operate more efficiently when they are run continuously and when used for trace heating of liquid lines and heating fat and molasses tanks.
It costs money to keep such liquids warm when a mill is idle. Pelleting plants perform better when kept warm. Compressors run more efficiently when run continuously and plants that are always kept running generally tend to be less troublesome than plants that are stopped and restarted.
The other significant factor in continuous running is the effect on the workforce. Operatives work much more efficiently when the temptation to shut down operations 30 minutes early on the last shift of the week is removed and when they do not have the opportunity to sit down for a chat at the beginning of the week.
Several factors that are specific and important to poultry feed operations are less consequential to other species of feeds. First, poultry feed tends to use a wider range of raw materials that vary in price quite markedly from those ingredients used in pig and dairy feeds.
We use more expensive liquids, often choosing to use different types of fats and oils, most of which are relatively high in energy and therefore expensive. Control of addition rates of these liquids can be crucial to effective cost control. We must choose our means of addition carefully.
With vegetable proteins being relatively expensive in comparison to cereals, it is important to ensure that "in-flight compensation" is monitored correctly and adjusted in the blending area. Ensuring that correct drive speeds on blending bin dischargers are being used is vital. When changing the designation of a bin from cereal occupancy to protein occupancy, it may be necessary to change pulley diameters to ensure that overuse of expensive proteins does not follow a change of use.
In mills where feed is sent to poultry grow-out sheds that produce birds at a given weight for age, it is critical to get the energy levels correct. This is especially true in mixed-sex flocks, where a factory needs birds of a precise weight on a given day. Merely taking an average weight over the whole flock does not allow the poultry meat processor to maximize slaughter percentages.
To achieve this, we need to have very accurate metering of liquids and preferably need to use loss-in-weight feeder principles to achieve precise additions. Daily inventory controls need to be employed and regular checks on fat temperatures need to be carried out since fat density and viscosity can be affected greatly by fluctuations in storage temperature.
Adequate dispersal of fats into both meal and pellets is affected greatly by the temperature of fat and pellets at the time of addition. We must monitor our mills carefully to establish what parameters work best for us.
Often, we need to preheat fat before adding it to pellets, and occasionally we need to heat both fat and pellets to gain maximum absorption. We must make sure pellets do not "give back" fat as they continue to cool after pelleting and when placed in bins. Good exhaust with adequate air flow through storage bins is essential to maintain optimum conditions for pellets in outloading bins.
I have always believed that overly bright and shiny pellets are a result of excess use of power through the press and a lack of lubrication. When this happens and the pellet becomes very hard and brittle, it also becomes quite impermeable and makes pellets hard to penetrate with fats and other liquids.
Keeping a relatively open texture to the outside of the pellet allows for maximum absorption, as does a slightly warm pellet that attracts fat toward its center and allows for maximum penetration of liquids. Control of air flow through coolers is imperative.
This open texture is a result of correct granularity selection, which leads us to the topic of use and application of hammermills, disc mills and rollermills in poultry feed mills.
In almost all poultry feed mills, hammermills are equipped with auto screen changers and employ the use of a sieves prior to grinding. This prevents the grinding of protected vitamins and other fractions of the grist that do not require any size reduction. It also assists in minimizing power consumption, but inherently all hammermills require high levels of power since they employ the technique of applying impact to the grains to shatter them.
This method of size reduction absorbs relatively high degrees of power in comparison to rollermilling, which applies pressure to crush the grains to reduce them in size. In several recent installations, I have noted a marked reduction in power consumption by utilizing disc mills prior to hammermilling. This reduces power consumption, significantly increases throughputs and allows for notable capacity increases at the grinding stage, with relatively little capital cost.
Jonathan Bradshaw is a consultant to the agribusiness and food processing industries, specializing in project management through his company J B Bradshaw Ltd. He has extensive experience in flour and feed milling in Africa, the Americas, Europe and the Caribbean. He may be contacted at: firstname.lastname@example.org.