Body mass loss of laying hens during long-term feed deprivation follows the pattern outlined by Cherel et al. (1988). Recalculations of BW data presented in Webster (2000) indicate that Phase 1 lasted about 3.5 d during which specific body mass loss averaged 47 g/kg per d.
Thereafter, Phase 2 continued for the remainder of the feed-deprivation period (18 d) with specific body mass loss averaging 15 g/kg per d during the first half of the period and 13 g/kg per d during the latter half. Total weight loss was 35% of the starting BW.
There was no increase of specific body mass loss rate to suggest transition to Phase 3. Similarly, in a study done more than a century ago, nitrogen excretion of feed-deprived domestic fowl was low and constant, consistent with the protein sparing of Phase 2, until the 24th d of starvation (Schimanski, 1879).
Nitrogen excretion increased after d 24, coincident with increased rate of specific body mass loss. The fowl were reported to retain vigor for the first week of Phase 3 but became motionless after the seventh day (d 31).