Effects of dietary zinc supplementation during a forced molt on subsequent hen performance and egg quality.


  • Rebwar Mohamad Ahmed Department of Animal Science, Faculty of Agriculture, University of Sulaimani, Kurdistan Region, Iraq. Author
  • Khasraw Abdulla Ali Halabja University, Kurdistan Region, Iraq. Author




Layer hen, Forced molting, Zinc, Egg quality


A total of 200 Hy- Line Brown commercial layer hens (64) weeks of age, were used in this study to investigate the impacts of different dietary zinc supplementation during a forced molt on subsequent hen performance and egg quality. The hens were randomly divided into (5) treatment groups of 40 hens each treatment. There were four replicate cages per treatment. The hens in the treatment 1 (control) were fed a layer ration containing 0 ppm ZnO, water and feed were provided ad libitum and received 16 hours of light/day, treatment (2) were fed a layer ration containing 28000 ppm Zn as zinc oxide for 11 days, treatment (3) 37000 ppm ZnO for 9 days, treatment (4) 46000 ppm ZnO for 7 days, and treatment (5)on-again, off-again program (ON-OFF).The experimental period was divided into seven periods (1) 64-66, (2) 67-69, (3) 70-72, (4) 73-75, (5) 76- 78, (6) 79-81, (7) 82-84 weeks. The results indicated that different levels of dietary zinc were improved Hen Day (H.D) egg production and egg weight at periods 70-72, 73-75, 76-78, 79-81, 82-84 weeks, except treatment 37000 ppm ZnO in period 70-72 was reduced in both egg production and egg weight, yolk and white weight improved also in these five periods above, feed intake was improved in two periods 70-72 and 73-75 weeks, feed conversion ratio was decreased in two periods 73-75 and 76-78 weeks, compared to both control and ON-OFF program. Haugh unit was improved in dietary zinc treatments and ON-OFF program in all periods except period 64-66 weeks compared to control. The percentage of weight loss was increased in the period 64-67 weeks for all treatments except control. Different dietary zinc supplementation was increased the concentration of zinc in yolk from 10.20 ppm (control) to 32.84, 29.61 and 51.08 and, white from 3.50 ppm (control) to 5.96, 5.90 and 6.37 ppm for 28000, 37000 and 46000 ppm during fed them with Zn for 11, 9 and 7 days, respectively, but the concentration of zinc in yolk and white was reduced week by week after following the refeeding of a control diet and was normally by week 6.


ALODAN, M. & MASHALY, M. 1999. Effect of induced molting in laying hens on production and immune

parameters. Poultry Science, 78, 171-177.

AYGUN, A. 2013. Effects of force molting on eggshell colour, egg production and quality traits in laying

hens. Revue de Médecine Vétérinaire, 164, 46-51.

BAR, A., RAZAPHKOVSKY, V., SHINDER, D. & VAX, E. 2003. Alternative procedures for molt

induction: Practical aspects. Poultry Science, 82, 543-550.

BAR, A., RAZAPHKOVSKY, V., WAX, E. & MALKA, Y. 2001. Effect of age at molting on postmolting

performance. Poultry Science, 80, 874-878.

BERRY, W. & BRAKE, J. 1985. Comparison of parameters associated with molt induced by fasting, zinc, and

low dietary sodium in caged layers. Poultry Science, 64, 2027-2036.

BERRY, W. & BRAKE, J. 1987. Postmolt performance of laying hens molted by high dietary zinc, low

dietary sodium, and fasting: egg production and eggshell quality. Poultry Science, 66, 218-226.

BRAKE, J. 1992. Mechanisms of and Metabolic Requirements for Complete and Rapid Reproductive

Rejuvenation during an Induced Molt: A Brief Review. Ornis Scandinavica, 335-339.

BREEDING, S. W., BRAKE, J., GARLICH, J. & JOHNSON, A. 1992. Molt induced by dietary zinc in a low-

calcium diet. Poultry Science, 71, 168-180.

CHRISTMAS, R., HARMS, R. & JUNQUEIRA, O. 1985. Performance of Single Comb White Leghorn hens

subjected to 4 or 10-day feed withdrawal force rest procedures. Poultry Science, 64, 2321- 2324.

DURMUS, I., ATASOGLU, C., MIZRAK, C., ERTAS, S. & KAYA, M. 2004. Effect of increasing zinc

concentration in the diets of Brown parent stock layers on various production and

hatchability traits. Archiv fur Tierzucht, 47, 483-489.

EL-DEEK, A. & AL-HARTHI, M. 20 04. Post molt performance parameters of broiler breeder hens

associated with molt induced by feed restriction, high dietary zinc and fasting. International Journal of

Poultry Science, 3, 456-462.

HASSANABADI, A. & KERMANSHAHI, H. 2007. Effect of force molting on postmolt performance of laying hens.

Intenational Journal of Poultry Science, 6 (9): 630-633, 2007. ISSN 1682-8356.

JACKSON, N., GIBSON, S. & STEVENSON, M. 1986. Effects of short-and long-term feeding of zinc oxide-

supplemented diets on the mature, female domestic fowl with special reference to tissue mineral content.

British Journal of Nutrition, 55, 333-349.

LEE, K. 1984. Feed restriction during the growing period, forced molt, and egg production. Poultry Science, 63,


MCCORMICK, C. C. & CUNNINGHAM, D. L. 1984a. Forced resting by high dietary zinc: tissue zinc

accumulation and reproductive organ weight changes. Poultry Science, 63, 1207-1212.


MCCORMICK, C. C. & CUNNINGHAM, D. L. 1984b. High dietary zinc and fasting as methods of forced

resting: a performance comparison. Poultry Science, 63, 1201-1206.

NORTH, M. & BELL, D. 1990. Commercial Poultry Production manual. Chapman and Hall, London, 800- 820.

PALAFOX, A. & HO-A, E. 1980. Effect of zinc toxicity in laying white leghorn pullets and hens. Poultry

Science, 59, 2024-2028.

PARK, S., BIRKHOLD, S., KUBENA, L., NISBET, D. & RICKE, S. 2004. Effects of high zinc diets using zinc

propionate on molt induction, organs, and postmolt egg production and quality in laying hens Poultry

Science, 83, 24-33.

ROLAND, D. & BRAKE, J. 1982. Influence of premolt production on postmolt performance with

explanation for improvement in egg production due to force molting. Poultry Science, 61, 2473- 2481.

SAID, N., SULLIVAN, T., BIRD, H. & SUNDE, M. 1984. A comparison of the effect of two force molting

methods on performance of two commercial strains of laying hens. Poultry Science, 63, 2399- 2403.

STEEL, R. G. D. & TORRIE, J. H. 1960. Principles and procedures of statistics. Principles and procedures of


STEVENSON, M. H. & JACKSON, N. 1984. Comparison of dietary hydrated copper sulphate, dietary zinc oxide

and a direct method for inducing a moult in laying hens. British poultry science, 25, 505- 517.

WEBSTER, A. 2003. Physiology and behavior of the hen during induced molt. Poultry Science, 82, 992- 1002.

ZIMMERMANN, N., ANDREWS, D. & MCGINNIS, J. 1987. Comparison of several induced molting

methods on subsequent performance of single comb White Leghorn hens. Poultry Science, 66, 408-417.



How to Cite

Effects of dietary zinc supplementation during a forced molt on subsequent hen performance and egg quality. (2015). Journal of Zankoy Sulaimani, 17(3), 215-224. https://doi.org/10.17656/jzs.10415