Tracie, another sure-fire indication of impending kindling is the HAY MOUSTACHE ... so, if you remove the box (due to using it as a litter box - ugggh) and subsequently see her gathering hay (and usually making a BIG production out of it! LOL), then put the box back in and provide more nest building material.
Also, there are many reasons for does to go longer than 31 days ... a fright by a predator, a fright by an unexpected/unusual noise, first time kindling, tenth time kindling, shy doe, buck cage too close, other doe cage too close, too hot, too cold, too wet, too dry, you are hovering ... ummm, I am sure there are more that I just can't think of right now
Basically, these are brand new to you does so you can only wait and see. If they go past day 35 and there is absolutely NO CHANCE of a later breeding, then call it a miss and rebreed immediately. Also, the act of breeding can start delayed labor, so you might end up with a nursing pregnant doe that will kindle in 4 weeks, so be prepared. It will not harm the doe, it will not cause the kits to be neglected or shorted in any way, just that they will be weaned at 3-4 weeks which is not going to hurt them at all either.
On another meat rabbit forum, several breeders had worked their stock to immediate breed back with weaning the kits over the 2-3 week age with the intention of getting the kits on pellets as soon as possible because they gained more weight, quicker, the sooner they went on pellets. A good commercial breed such as Calis have many lines that can physically stand this intensive breeding schedule, but the brood does are "done" at about 2-1/2 to 3 years of age. The overriding consideration when aiming for this type of breeding schedule is the health and vitality of the doe ... some could take the schedule all year, some only half the year needing a month or two layoff to rebuild condition, others couldn't handle more than 3-4 litters per year.
Whatever your plans/needs, there are many different procedures to achieve all levels of production and you will eventually settle into what works best for you and your herd. We are just "along for the ride" as you figure things out (the fun part of raising rabbits!!!!)
