Giraudeau, M., Czirjak, G., Duval, C., Bretagnolle, V., Gutierrez, C. & Heeb, P. (2014) An experimental test in Mallards (Anas platyrhynchos) of the effect of incubation and maternal preen oil on eggshell microbial load. JOURNAL OF ORNITHOLOGY , 155(3), 671-677.