Suzanne, I also have a small flock of laying hens and have made Tiramisu many many times with the raw eggs from my girls. You need not worry about a thing, your eggs are healthier and more germ and bacteria free then any store bought egg. I take no extra precautions with washing the shells either, as long as they are clean (don't have mud or chicken poop on them)
My recipe calls for seperating the eggs then beat the whites with a pinch of sugar until soft peaks form and to mix the raw yolk in with the marszcapone cheese along with a bit of espresso and I always throw in a shot of booze! Fold in your egg whites and layer up with your lady fingers soaked in coffee. BTW tastes just as good made with plain old layer cake. Anyway, I have made this for years and have kept laying hens for probably close to 15 years now and have never ever had a problem with food borne illness. I also make chocolate mousse with uncooked eggs.