I'm going to make a couple of assumptions--it sounds to me like the professor thought your birds to be pure RIR, and I believe he was stating that ALL of the offspring would be 50% RIR, 50% thai-bird, not that half of the offspring would be pure RIR and the other half pure thai-bird.
Another possibility, although it negates the idea that they are pure RIR, is that he considers your current birds to be red sex-links, and understood you to be asking if crossing them to a large rooster would create more sex-links. If that is what he meant, he is correct--offspring of sex-links are not sex-linked.
I am thinking there may have been a communication barrier.
If you want RIRs, you need to find and RIR rooster. If you merely want birds that lay well, then any male from a breed known for laying well should work.
Another possibility, although it negates the idea that they are pure RIR, is that he considers your current birds to be red sex-links, and understood you to be asking if crossing them to a large rooster would create more sex-links. If that is what he meant, he is correct--offspring of sex-links are not sex-linked.
I am thinking there may have been a communication barrier.
If you want RIRs, you need to find and RIR rooster. If you merely want birds that lay well, then any male from a breed known for laying well should work.
