Thanks for the replies from the two of you. You both seem to recommend very different methods, and RDR's is also totally different from either of those (I know that there are many ways to skin a cat, or breed a rat)

Suzuki, I believe that you are stating that you keep 1.4 per concrete tub and never move male or females, even for birthing/nursing, correct? This is basically what I've been doing for a year and for some reason I do not get a good production rate... eaten babies, females that just never get pregnant, etc.

And Littleindiangirl, I read your posts in the sticky and am somewhat confused about your method as well. You talk about the cycle of moving males from one female to the next every two weeks, but you also state that you use concrete tubs with 1.3 I believe. Could you clarify a bit for me? If you move a male on a cycle of 2 weeks through 0.3 tubs, are you letting the females all give birth in the same concrete tub? But if you do only have 1 female per tub like the graph shows what happens if one of the females doesn't get pregnant in the two weeks allowed... you just don't have the litter that week that you are counting on?

I will have to say that I like things about all three systems, and I can also see potential problems with each. (The following statements are made assuming that I understand how your systems work). I think that Suzuki's is the simplest with less moving and sorting and not as many different kinds of racks, and also is not feeding females and taking up space during weeks of rest, however this is basically what I've been doing with poor results for some reason. RDR's seems that he would produce the most amount of pregnant rats per week because the moms stay in the breeding bins until they are pregnant and then moved into a safe (however small) bin to give birth and nurse, but with this system there is no way to keep track of how old each female is or if she ever does get pregnant at all. Littleindian girl, I like yours because if one female is kept per bin it would be very easy to keep track of who's producing and how old they are, but it seems that this would take up alot of space and if a female missed getting pregnant or had a low number in her litter your numbers would be greatly affected that week.

Ok, so I over analyze everything I do, but it usually pays off for me. If I have incorrectly assumed anything about either of your setups I apologize and ask you to please correct me. Thanks again.