I love this article about the rats age and how they have come up with this tablet. If you think about it. Al makes sense.
It's not recommended to breed on rats before the age of 5-6 months. Preferred even later. But also it's not good to breed on to old rats as a bigger risk for complications in the older body. And al litters do deplete on the female rat. Looking at this tablet and how they came to the ages in human years. You get a good understanding on why not breed rats to early. Their body and mind are not ready. Think about a 6-month rat as if it was an 18-year-old human girl. Or a 60-year-old woman if you would even consider breeding a 2-year-old rat female. That just sounds weird.
Extremely interesting article I do recommend to read.