Some girls can be "infected" with eggs. This is good and bad.
Good: they can lay egg in empty locker
neutral: new locker will be random type.
bad: if someone report infected girl that will rise alert.
Girl can be infected after multiply captures. But don't know, after which capture she is infected. Girl can be infected more then once. If she have more eggs it means she can ad more lockers for you, but she can be spotted more easy. So you one one side want to plant many eggs in one girl to grow faster, but that leads to simpler detection, which is bad for you. So try to find balance. And some luck. Some girls can be infected with first egg on second try, but some can be infected. And you don't know if you where successful immediately. Egg need some time to grow. And you can detect it, before it reaches "first" stage. I think one maybe two eggs per girl is relative safe option for you. More is more dangerous but more rewarding. For example girl may lay two eggs in one locker with leads to faster growth.