Laying hen welfare is gaining importance in the United States and several states have passed legislation for a welfareriendly housing environment, which has forced the egg industry to explore alternative housing environments. For this reason, our first objective was to determine the effect of housing environment and laying hen strain on production performance and egg quality. Results showed that production performance of the hens raised in the alternative housing system was similar to the conventional system. The second objective was to compare the eggshell and cloacal microbiology. Our results indicated that the microbial load observed was higher in the alternative system compared to the conventional system. The third objective was to determine the effects of housing environment and laying hen strain on tibia and femur bone properties. The results demonstrated that the alternative system provided better tibia and femur bone characteristics, but it varied among laying hen strains.

Dissertation summarizes the results of computational and experimental modeling in the field of biomechanics engineering. Analyses are focused on selected variables that complement or can supplement existing methods of prediction of bone fractures. In terms of computational modeling the variables are based on stress strain analysis. The greater part of the work has been aimed on experimental modeling which is used for monitoring the two dominant components of bone tissue, which are minerals and collagen fibers. The current most widely used variable for the description of bone loss (osteopenia, osteoporosis) is areal bone mineral density (BMD). This variable does not however provide any information about the change in total volume consequently change of mineral and collagen. Proposed mechanical values follow the loss of the two components during simulation of minerals loss (demineralization) and simulation of collagen loss (deproteinization) in vitro for long turkey bones