Abstract: The eggs are incubated in a stack of relatively spaced liquid containers, each of which has a basin therein through which the incubation liquid undergoes upward flow and then weirs over opposing sides of the basin into outflow chambers from where it discharges into the container therebelow. In the lower container, the liquid is introduced into inflow chambers at opposite ends of the basin, where it flows downward through ports into a plenum and then upwardly into the basin of the lower container and over the sides of the same in the aforedescribed manner. At the fry release stage, a gate is removed at the top of one of the opposing sides of each basin, and in the space between the containers there is a spigot-like conduit means which discharges the liquid from one of the outflow chambers of the upper container into the lower container at a delivery point on an arc passing vertically above the basin of the lower container.