The yellow-eyed penguin is a threatened species endemic to New Zealand and its subantarctic islands. Survival and fledging success vary from year to year partly in response to changing food availability. Mortality in ‘poor food’ years may potentially be reduced if adults are allowed to rear only one of their two chicks. Conservation managers have therefore deliberately reduced broods to one in some recent breeding seasons, but the merits of this policy are controversial. We investigated, by simulation modelling, the conditions under which a policy of artificial brood reduction would enhance population growth. Food supply may be difficult to predict from early-season indicators so we also considered the effect of forecasting errors. Artificial brood reduction can increase the population growth rate, even in the presence of moderate forecasting errors, given a large enough cost of breeding. However, field studies suggest that the required cost of breeding is unrealistically large and the policy is unlikely to be a useful management tool for yellow-eyed penguins.