Meira, M., Afonso, I., Ribeiro, V., Dantas, R. and Brito, N.V. 2023. Sustainability of the Portuguese autochthonous hens breeds: characterization of the productive system (eggs). Scientific Letters. 1, Sup 1 (Apr. 2023). DOI:https://doi.org/10.48797/sl.2023.55.