They can run but they can't hide, and that's bad news for growing chicks

Chicks raised in featureless cages may fail to develop key skills

source: Betsy Mason
New Scientist no 2354, August 3 2002 p18

Wire cages for battery hens are to be banned in the European Union (EU), but replacing them with featureless pens could hamper the development of chicks. The new EU directive sets out a maximum per square metre of nine birds. Ralph Freire, a researcher from Purdue University, Indiana, has found that chicks raised in featureless pens tend to crowd, and can even suffocate, as well as become aggressive and suffer malnutrition. Chicks normally starts to leave their mothers at the age of 11-days-old, and being separated from their mothers, with mother and chicks unable to see each other, seems to help chicks to understand space. Freire imprinted chicks using a tennis ball, and tested whether they could find the ball when it was hidden behind a screen. Birds that had grown up in pens with barriers tried searching behind a screen. Chicks raised in featureless pens did not attempt to locate the ball. Meanwhile, ethologist, Linda Keeling, working in Sweden, has also found that chicks need to learn to perch while they are young, or it is very difficult for them to learn later.