 One study showed that 24.6% of hens from battery cages had recent keel fractures whereas hens in furnished cages, barn and free-range had 3.6%, 1.2% and 1.3% respectively.However, hens from battery cages experienced fewer old breaks (17.7%) compared to hens in barn (69.1%), free-range (59.8%) and furnished cages (31.7%).Flocks are sometimes force moulted, rather than being slaughtered, to reinvigorate egg-laying.