Such actions are making us acutely aware of the "law of diminishing returns." We are now faced with a more accurate evaluation of the application of the "law" to the broiler chicken of today, the facility in which the chicken is grown, the feed the chicken is fed and the grower who manages it all.

The broiler chicken of today is truly remarkable. The superior genetics has resulted in increased body weight gains, increased yields, and increased efficiency of feed utilization. In Western Canada, managing the rapid growth rate has become our number one priority. To accomplish this task, the grow facilities are usually equipped with computers to consistently control the bird's environment. Feed formulations have been improved. Water and feed delivery systems are being improved. All of this investment in equipment and time will ensure the bird reaches its full potential. But, will this still be the case with increased bird densities?

The health implications for higher density broiler production are significant and must be taken into account. Bird welfare, in my opinion, must also be considered. Bird welfare, is not going to be, it is, extremely important in terms of meeting the consumer demands of today and tomorrow. What happens when we add more kilograms of live weight to a given, fixed amount of floor space? As we examine the possibilities, we should always evaluate our FLAWS.

With increased density, feed and water will become more difficult for each bird to access. This will lead to reduced performance on each normal bird. Furthermore, birds which may only have a marginal disability will become less able to compete as the stocking density rises.

Poorer litter conditions associated with higher moisture content occur with higher stocking densities. Higher litter moisture will "increase the wave of insult" by increasing the concentration of pathogenic organisms. Reduced access to feed containing anticoccidials/antibacterials together with increased exposure to oocysts/bacteria may result in clinical coccidiosis and/or bacterial infections. Poor litter conditions can also exacerbate leg disorders experienced by chickens.

Poorer litter conditions, reduced access to feed, and an increased demand for fresh air may result in an increase incidence of pulmonary/cardiovascular disease. Presently, we are faced with an ever increasing incidence of pulmonary hypertension (ascites). By increasing the stocking density we will be increasing the demand for vital oxygen. Increasing the demand for oxygen will add more pressure to the bird's pulmonary and cardiovascular systems.

Increasing stocking density will increase the likelihood of a bird being scratched. This coupled with an increase in litter moisture will set up the possibility for an increase in the incidence of type II cellulitis. There are many "roads that lead to the cities of ascites and cellulitis" and increasing the stocking densities will only make "these roads easier to travel."

The ability to vaccinate our birds via the drinking water will be compromised by increasing the stocking density. Poorly vaccinated flocks are more prone to vaccine "rolling" reactions and are more prone to disease.

Increased stocking densities will increase stress. Increased stress will manifest itself in many ways, most commonly as a reduction in overall performance. Increased stress will result in an increased susceptibility to the common broiler diseases in a given geographical area and may open the door for new and re-emerging diseases.

If we increase the stocking density of our broiler chickens beyond our capabilities as broiler farm managers, then we will suffer losses. If we increase our capabilities as broiler farm mangers, then we will be able to grow more chickens in less space. Let us first increase our capabilities, then add more chickens.

As a poultry veterinarian today, the majority of my work has revolved around solving "problems" that involve more than one etiology or cause. It clearly involves concentrating on prevention. "Magic bullets" do not exist. The diseases that we are faced with "preventing" have multiple and convoluted causes and involve the understanding of all disciplines of broiler production.

Our broiler chickens have served us extremely well in the past and by all present indications our broiler chickens today are performing even better. More commitment will be required by the entire broiler production team. This team will be required to operate and work together in an orchestral fashion in order to achieve success.

Note: British Columbia Chicken Marketing Board Quota Minimum Floor Space is 2.57 kilograms of live weight per square foot of floor space.

September 2006