I have been having a PM discussion with a very knowledgeable person on anima husbandry here on BYC. I have decided to share with you my experiences and (ahem) successes, even though this has nothing to do with chickens per se.
Trying to breed anything is a pain in the rear!
I have never tried rabbits. I can believe you easily. It seems the chances of an anima becoming pregnant is inversely proportionate to the value of the offspring and the desires of the owner.
I have a white Lab (dog) A variation of a yellow lab. I paid huge dollars for this dog, I spend lots of time training her and when she needed more training than I could do I sent her to boarding school. My Wife was not happy over the money I spent on this dog. I did everything I could to make her offspring valuable. She is a fantastic dog, She kills at field trials. When hunting she does everything but clean and cook Pheasants and Ducks.
I had her breed to a high priced male with duel registration US and UK. She threw 11 pups. The male was chocolate. What I did not know at the time was dog genetics. My dog could only have yellow ( white) pups or Black. The male could only have Black or brown pups. So I got 11 black pups.
Still good pups with great papers, just not chocolate or yellow. BUT I stumbled into a potential gold mine of labs. The pups while back were capable of having all three color pups in one litter with the right father. I kept one pup from the litter. The female alpha.
I did not want my dog to be a puppy mill. I did not want to ruin her "looks" or health by having excessive litters. Besides having genetics I wanted she was my best friend. I went to breed her 3 years later. To make a long story short she did not take, but had a false pregnancy which because of a tumor on her uterus. I had to have a hysterectomy on her. End of my ever getting my money back from her.
But I had her pup. Well, the pup was not the dog the mother was. She did not have confirmation and mind set of the mother. BUT she had genetics in her to have a pup that did. (My brother took the runt of the litter, that did have the confirmation, looks and mind set to be a champion, and same genetics and he spayed her!!!!! Before he knew she was going to be the dog she was....(Dang Brothers)
An Alpha pup is a pain in the rear to train. They do not have that burning desire to please a master/alpha other dogs have. They have a desire to be the alpha and that is all! Smart as a whip, but does what she wants to do and spends as much time training me as I did training her. Great hunter, enjoys it, brings me every kill, just does not take orders well. The good thing is I did train her to eave my birds alone. Besides why would she ever kill the one thing that feeds he treats all day long.
I decided to breed her and get one of these rainbow litters of all three colors of labs. The vets say she is in perfect health to carry a litter. I have mated her 7 times now ( over 4 years) and she does not take! Another I told you so from my wife..... I still want to breed her but I have given up on success. I want the right make dog which is hard to find. and to make matters worse it is very hard to tell when my pup comes into heat. She keeps herself so clean we do not notice it every cycle no matter how hard we look for it...
BUT I am willing to bet if the neighbors German shepherd, Spaniel mixed mutt every gets close to her she will have 23 worthless cute little mutts.
This is why I am satisfied raising mutt chickens, for now, I know I will never get the outcomes I want/need/desire.