How to design a flock

The EFG Broiler model makes use of one variable from each of the input folders to define the inputs for each simulation, but it is possible to set up, and run, more than one simulation at a time. This is equivalent to setting up an experiment, in which the effects of, for example, different breeds, different feeding programmes, or different environmental temperatures may be compared. The ability to set up experiments of this nature is one of the powerful features of this simulation model.

To create a new flock, right-click on a flock folder in the flock section and choose New, Flock from the pop-up menu.

A flock is created by dragging at least one item of each type into the flock. Additional factors may be created in the Flock section by entering multiple values for some of the variables. See Setting multiple values for a variable in a flock.

Screenshot of the Experiment Values dialog box

Under the Design tab of the flock details, values may be entered for the following variables:

Number of birds at start

This is used in revenue and cost calculations only, and has no effect on the biological results of the simulation.

Initial stocking density

This must be stipulated so that the stocking density prevailing thereafter, taking account of mortality, can be calculated.

Percentage males

The EFG Broiler model simulates the performance of male and females broilers simultaneously, so any combination of males and females in a flock may be simulated by multiplying their performance with the proportion of each sex in the flock. One or more values may be given for the initial percentage males in the flock. If the flock is to consist of female birds only, then enter 0. Similarly, a value of 100 indicates a flock containing male birds only. The model calculates a daily value for the proportion of males in the flock by adjusting this initial value by male and female mortality, and any cropping that may have occurred. The daily value is then used to calculate a weighted average of the results calculated for a male and a female bird.

Male and female day old chick weight

The weight of the male and female birds at the start of the simulation must be specified. This will usually be the weight at hatching, but any weight up to approximately half the mature body weight may be entered. For day-old chick weight a value of 50g is suggested for initial use. The user should be aware that, by starting a simulation at a weight other than that at day-old, the effects of diet and environment prior to that weight will not be reflected in the state of the bird at that time, nor will the age of the bird necessarily correspond to the body weight. The simulation period is measured as time, not as age.