I have a smattering of forms that I use to keep track of life here on Dandelion Hill. Since they are docs and spreadsheets, you can download them and alter them to work for your setup. And they’re free!
bunny breeding record
I have one of these sheets for each of my rabbits. It includes individual info and a line of info for each litter (including an average weight for kits at 4, 8, and 12 weeks). Room for notes at the bottom. I can see how each bunny is faring by studying the content.
This sheet tells me how many kits were born during a given year and where they went. The light grey total boxes do the figuring for you. (My columns reflect bunnies that make it to 12 weeks (or are sold at 8 wks or more). I do keep track of any losses in the far right column. It’s a way of keeping an eye on the health of my rabbitry.)