title: Estimate the contribution of incubation parameters influence egg hatchability using multiple linear regression analysis.
abstract: OBJECTIVE
  This research was conducted to determine the most affecting parameters on hatchability of indigenous and improved local chickens' eggs.
  
  
  METHODS
  Five parameters were studied (fertility, early and late embryonic mortalities, shape index, egg weight, and egg weight loss) on four strains, namely Fayoumi, Alexandria, Matrouh, and Montazah. Multiple linear regression was performed on the studied parameters to determine the most influencing one on hatchability.
  
  
  RESULTS
  The results showed significant differences in commercial and scientific hatchability among strains. Alexandria strain has the highest significant commercial hatchability (80.70%). Regarding the studied strains, highly significant differences in hatching chick weight among strains were observed. Using multiple linear regression analysis, fertility made the greatest percent contribution (71.31%) to hatchability, and the lowest percent contributions were made by shape index and egg weight loss.
  
  
  CONCLUSIONS
  A prediction of hatchability using multiple regression analysis could be a good tool to improve hatchability percentage in chickens.
authors.affiliation: Department of Poultry Production, Faculty of Agriculture, Aflaton St., El-Shatby, University of Alexandria, Alexandria, Egypt.
authors.forename: Mohamed H
authors.initials: MH
authors.lastname: Khalil
authors.affiliation: Department of Poultry Production, Faculty of Agriculture, Aflaton St., El-Shatby, University of Alexandria, Alexandria, Egypt.
authors.forename: Mostafa K
authors.initials: MK
authors.lastname: Shebl
authors.affiliation: Department of Poultry Production, Faculty of Agriculture, Aflaton St., El-Shatby, University of Alexandria, Alexandria, Egypt.
authors.forename: Mohamed A
authors.initials: MA
authors.lastname: Kosba
authors.affiliation: Department of Poultry Production, Faculty of Agriculture, Aflaton St., El-Shatby, University of Alexandria, Alexandria, Egypt.
authors.forename: Karim
authors.initials: K
authors.lastname: El-Sabrout
authors.affiliation: Department of Poultry Production, Faculty of Agriculture, Aflaton St., El-Shatby, University of Alexandria, Alexandria, Egypt.
authors.forename: Nesma
authors.initials: N
authors.lastname: Zaki
keywords: chickens; hatchability; multiple regression; path coefficient; prediction