This one caused me to shake my head in despair.another example of cecectomy as routine procedure in poultry feed research:
"In studies regarding the efficiency and digestibility of feeds, cecectomy technique that was first described by Durant (1929) is usually used. It makes possible to perform the digestibility tests in short time and at less cost as compared to conventional growth trials (Pupaet al., 1998). It eradicates the interference factor of the cecum; thus, each group or individual bird can present a specific bacterial microbiota and cause interference in the digestibility studies (Pan and Yu, 2014)." That's a paper from 2019. https://www.sciencedirect.com/science/article/pii/S0032579119306960
A natural digestive organ and its function is not 'interference' for the chicken whose organ that is. Rather, its elimination makes the work cheaper and easier for the researchers. Recent work on the microbiome has shown that what goes on in the caeca is the extraction of more nutrients for the chicken, either directly, or via the trillions of microbes that live in them.
So, if I have understood correctly, for the sake of doing the research more quickly they create an environment (a chicken without a caecum) that makes the results of the research essentially invalid.
Leave aside the issues of how they are treating the chicken, that is just bad science!