If Yeshka had passed her 'knowledge planes' check she might have realised that hell hounds can breed with pretty much any creature (which is standard for D&D races) and that once pregnant, anything short of a wish spell or a divine miracle is ineffective in preventing the birth. An average of 5 pups will be born in a litter. On the plus side, the pregnancy only lasts three months and the hell hounds can look after themselves after a year and reach full maturity after only three years. It's going to be a busy year for Yeshka...