Consideration should be given to the question of animal welfare before installing new equipment or adopting new husbandry systems. In general, the greater the restriction imposed on an animal and the greater the complexity of the system or the degree of control that is exercised over temperature, air flow, or food supply, the less the animal is able to use its instinctive behaviour to modify the effect of unfavourable conditions and the greater the chance of suffering if mechanical or electrical failure occurs. Thus, systems with a high degree of control over the environment should be installed only where conscientious personnel, skilled in both animal husbandry.
