To give background, these rats live in England, are originally from the sewers under local towns but have moved into a big protected park and are living completely wildly. The rats are also in monogamous relationships.
My question is, what's the maximum number of litters a female rat can have in a year without it severely damaging her health?
The rats are supposed to be breeding heavily but since these are intelligent talking animals I am assuming there would be a level of control so the females don't end up getting harmed through constant pregnancy.
When I tried searching for this information I tended to just find results for how many babies a pet rat should have and how many a wild rat will typically have. I'm asking for closer to a maximum amount.
Thank you to any rat experts there may be among here.