Horton, G. M. J., Malinowski, K., Burgher, C. C. et al. 1991. The effect of space allowance and sex on blood catecholamines and cortisol, feed consumption and average daily gain in growing lambs. Applied Animal Behaviour Science 32, 197-204.

Reducing the [barren] space allowance from 0.99 to 0.62 sq.m per lamb reduced feed intake and average daily gain. .. There was no effect of pen size on plasma epinephrine, norepinephrine or cortisol concentrations. .. The results show that the highest performance was achieved under the conditions we believe to be associated with the best welfare status, although none of the evidence showed a decline in welfare as measured in the three endrocrine parameters.