Don’t trust the term “Plymouth Rocks”. To a lot of people it means Barred Rocks but I’ve seen people consider all Rocks “Plymouth”. Most of the time it means barred but not always. A lot of people that use it to mean only barred rocks may not believe me but check out Henderson’s Breed Chart. You don’t find Rocks under “Rock”, you find all the rocks under Plymouth Rock.
Henderson’s Breed Chart
http://www.sagehenfarmlodi.com/chooks/chooks.html
I’ll probably add to your stress level and try to explain why you get such conflicting comments on certain breeds. I agree certain breeds have tendencies but I find strain to be more important than breed in many cases. What do I mean by “strain”? If the person selecting which chickens get to breed uses certain criteria when selecting those chickens, in a few generations they have a flock with those traits enhanced or almost eliminated. If they don’t select for a certain trait, that flock can be all over the place on that trait. This applies to behavioral traits as well as physical or production traits. Each hatchery has a different person selecting which chickens get top breed and each breeder is also unique. They each have their own criteria that they use, that might include certain behaviors, it might not. That might include certain physical characteristics or production characteristics, it might not. That means you can get a Wyandotte from one flock that will have different characteristics than a Wyandotte from another flock.
To make it even more difficult, you have to have enough for averages to mean something. Each chicken is an individual with its own personality and traits. An example. If you select your breeding hens so that they never go broody in a few generations you will have a flock that hardly ever goes broody. Certain production breeds like Rhode Island Reds have that reputation and many of those flocks were bred for decades to not go broody. Most won’t but occasionally one will even from this flock. Then if you get a breeder that wants them to go broody or doesn’t care, you can get a flock of RIR’s that actually do go broody regularly.
To demonstrate the power of strain. I saw an article a few years back where a breeder split a flock into two flocks and started breeding them for size. I think these were White Rocks (or White Plymouth Rocks if you wish) but I’m not sure. One flock was bred to be big, one small. I don’t know how long he had been doing this but he then had one flock than the average weight was 9 times the other flock average. As far as parentage goes, these were still purebred chickens of the same breed but were different strains.
Since you only want two averages are not going to mean a lot. Breeds do have tendencies so I suggest you look through things like Henderson’s Breed Chart and just select two. Whether that is two of the same breed or two different breeds or colors doesn’t really matter. Even the ones that suggest colors matter seem to pretty much agree that they will all get along. There is some luck involved but the odds are pretty good you will be happy with whatever you choose. And the rooster really won’t care.
Henderson’s Breed Chart
http://www.sagehenfarmlodi.com/chooks/chooks.html
I’ll probably add to your stress level and try to explain why you get such conflicting comments on certain breeds. I agree certain breeds have tendencies but I find strain to be more important than breed in many cases. What do I mean by “strain”? If the person selecting which chickens get to breed uses certain criteria when selecting those chickens, in a few generations they have a flock with those traits enhanced or almost eliminated. If they don’t select for a certain trait, that flock can be all over the place on that trait. This applies to behavioral traits as well as physical or production traits. Each hatchery has a different person selecting which chickens get top breed and each breeder is also unique. They each have their own criteria that they use, that might include certain behaviors, it might not. That might include certain physical characteristics or production characteristics, it might not. That means you can get a Wyandotte from one flock that will have different characteristics than a Wyandotte from another flock.
To make it even more difficult, you have to have enough for averages to mean something. Each chicken is an individual with its own personality and traits. An example. If you select your breeding hens so that they never go broody in a few generations you will have a flock that hardly ever goes broody. Certain production breeds like Rhode Island Reds have that reputation and many of those flocks were bred for decades to not go broody. Most won’t but occasionally one will even from this flock. Then if you get a breeder that wants them to go broody or doesn’t care, you can get a flock of RIR’s that actually do go broody regularly.
To demonstrate the power of strain. I saw an article a few years back where a breeder split a flock into two flocks and started breeding them for size. I think these were White Rocks (or White Plymouth Rocks if you wish) but I’m not sure. One flock was bred to be big, one small. I don’t know how long he had been doing this but he then had one flock than the average weight was 9 times the other flock average. As far as parentage goes, these were still purebred chickens of the same breed but were different strains.
Since you only want two averages are not going to mean a lot. Breeds do have tendencies so I suggest you look through things like Henderson’s Breed Chart and just select two. Whether that is two of the same breed or two different breeds or colors doesn’t really matter. Even the ones that suggest colors matter seem to pretty much agree that they will all get along. There is some luck involved but the odds are pretty good you will be happy with whatever you choose. And the rooster really won’t care.

Plymouth Rocks can also be white, Partridge, etc...
That's why the Wyandottes are next for freezer camp, they aren't good enough to continue breeding for my expectations, and I blame the Hatchery lol 