Effect of different methods of forced molt on performance of laying hens

Abstract

One experiment was conducted to compare productive performance of laying hens of two strains: Babcock (light) and Hisex Brown (semi-heavy), exposed to forced molt according to the following treatments: A- Feed restriction (11 days), B- Salt restriction (42 days), C- high dietary zinc (2.0% of ZnO during 11 days) and D- High dietary iodine (0.6852% de KI during 42 days). The experimental design was a random block design. The birds (128 by strain) were 66 weeks old at the beginning of the molt phase. Birds on treatments A and C had better production in the second cycle and better feed conversion. Birds on treatment A produced the heaviest eggs with lowest quality (both internal and external). Percentage of production was not different among the strains tested, even though the lightweight birds showed a significantly better feed conversion and lower feed consumption. The semi-heavy strain produced significantly heavier eggs, with better internal quality but lower shell quality.