The ClosedCounterPOPd software uses a population matrix model to compare the real and hypothetical population-scale impacts of lead in hypothetically closed bald eagle systems. The CounterPOPd app uses the outputs from a combinatorial optimization algorithm in conjunction with adult time series data of bald eagles to compare the asymptotic and transient population dynamics with and without lead toxicosis. Comparative demographic quantities include the annual abundances, bi-annual abundances, migration, growth rates (asymptotic, transient, cumulative, and stochastic), stable stage distribution, reproductive value, survival rates, sensitivities, elasticities, damping ratios, convergence times, and more. The software also provides interpretation for each demographic quantity from the modeling, biological, ecological, and resource management perspectives. The ClosedCounterPOPd app is programmed to compare a closed population with and without lead, but it may be modified to assess the population scale impact of other veterinary maladies. For similar analyses given an eagle system that is open to dispersal, please use the CounterPOPd app (https://doi.org/10.7298/0v1k-wq39).