Memes

Feel free to cite your source. If you're thinking of the idea that chickens may have more conservative genomes than most other birds, then I get where you're coming from, but we don't actually know what T. rex's genome looked like to be able to compare them. It's entirely possible that the T. rex genome would have changed in a lot of places where the chicken genome is relatively conservative, making chickens no more similar to T. rex genetically than any other bird is. That aside, all birds evolved from the same node on the cladogram, which was already pretty far removed from tyrannosaurs at that point. Saying chickens are more closely to T. rex than other birds are would be like me saying I'm more closely related to my great uncle (whose DNA we do not have) than my biological sibling is because I have 25.01% of his brother's - my grandpa's - DNA and my sibling only has 25%. It's not provable because we will never recover the DNA to know the overlap. Even if we could prove that, it would only demonstrate that we are more related in a very strict genetic sense and ignore that we are exactly as related in terms of shared common descent.