Only if they are penciled, as your Chanteclers and in Partridge Rocks, etc. are. This is considered partridge in the EE. Partridge is just a Black Breasted Red (or Red Duckwing), when you breed these and get a rooster he is the same color as a Chantecler or Plymouth Rock rooster.
Baloney. What you have there is a non-true breeding, mixed genetic coloring. I have made enough crosses to know the difference, and have bred blue egg chickens since the early 1970's. The American Poultry Association defines partridge coloring, and that ain't it. The males may well come out black breasted, but that does not make it partridge.
EE chicks are sold by most commercial hatcheries so they are extremely easy to acquire.