You either breed rabbits for show, for pets, for your table, for your pets or for whatever reason. Matters NOT the reason.
BUT you are a breeder.
Now...let's say you have a rabbit that won't breed, or won't raise young, or won't produce offspring. What do you do? Not several rabbits ONE rabbit or possibly two.
DO you keep that rabbit for ages trying a variety of things? ACV in the water, putting with the buck every day for a month or two, wheat germ, colony, etc.
Seriously .. if you are doing this you need to ask WHY.
WHY would you want to add those poor breeding habits to your herd?
WHY would you want to add those poor mothering abilities to your herd?
WHY would you want to feed an non-productive rabbit for months on end?
The sheer number of people I hear of who for three or more months have been trying to breed their rabbits and finding that it simply not working. And they go...what else can I try? My response is get rid of that rabbit.
IF your other stock is producing you know it's not an issue with your animal management style.
So WHY keep that ONE rabbit who simply isn't fitting into your management?
Either turn that rabbit into a pet OR cull it.
Two kicks at the can is what my rabbits get here. I used to give them three tries to get it right and then said to myself..hold on... 98% of my rabbits get it all right the first time. Why on earth am I messing around with rabbits that don't want to work for me?
So if you have a rabbit that are you messing around with trying to get litters from and your other rabbits are producing just fine... ask yourself WHY am I doing this?