An in vivo investigation to determine instrinsic differences in optical activity of tissues of a three-day-old chicken embryo was performed. A homogenous flux of light at 514.4 nm from an argon ion laser was used to develop 13 of the 16 Mueller matrix components of backscattered light. The results show that all tissues backscatter light predominately in the same polarization state as that of the incident light. This effect manifests itself as large non-zero intensities in the diagonal terms of the Mueller matrix. Any change in polarization is distributed unbiased to the other polarization states as the off diagonal Mueller matrix elements each consists of a low intensity image. Depolarization by birefringent tissue structures such as collagen or actin-myosin fibers which would lead to non-zero intensities in the off diagonal Mueller matrix elements, is not observed. This may be due to the lack of such structures given the early age of the embryo.