It's a classic optimization problem. With high speed, but poor suitability, animals are bound to return. With low speed, but good suitability, there's low retur

It's a classic optimization problem. With high speed, but poor suitability, animals are bound to return. With low speed, but good suitability, there's low return rate - but slow turnover, which leads to overcrowding and rejection of new animals. Like in business and tech, you want a high as posible throughput / inventory turnover rate - but obviously with constraints.