The present housing systems for chicken and pigs lead to destructive pecking in chickens and tail biting in pigs. Wing flapping and stretching, flying, scratching, dust bathing, perching, meaningful socialization, preening of feathers and the use of a nest for laying their eggs are virtually impossible. Most of these behaviours are considered important with respect to the well-being of the hens. Such research and testing are very important and cannot always be replaced by other methods. But it is most important to spare the animals unnecessary suffering.
Ethical consideration is necessary.
The suffering of the animals must be taken into account - not only the value of the research and the testing. We are talking about the three R's. The first technique refers to alternatives which replace animal models. The most widely used nonliving model involves the use of modern chemical techniques to identify substances and to determine their concentration or potency. Another is the use of computer simulation as a means of virtually replacing the use of living animals.