As described in other posts, Mac had gotten his PhD in animal nutrition. He taught for a year in Tennessee, then moved east in 1930 to take a job with the Agricultural Research Service, at the Beltsville MD research center. He stayed there for 13 or so years, before moving to Massachusetts to become director of research for the Webster feed company. I remember Dad had some small items, pencils, pocket calendar, that sort of stuff, all with the Webster name on them.
Anyhow, Dad said that Mac had worked on the Beltsville turkey. Finally got around to researching that and here's what the ARS site says (pdf). The gist is in the wikipedia site:
The Beltsville Small White was developed beginning in 1934 in response to market research that said consumers wanted a turkey of small to medium size with no dark pinfeathers. In a breeding program at the Beltsville Center that lasted from 1934 to 1941, the USDA used White Holland, White Austrian, Narragansett, Bronze, and Wild Turkey genetics. The breed was used commercially in the 1940s, and was recognized officially by the American Poultry Association in 1951.To be honest, I've not seen a document linking Mac to the turkey, but then I've not specifically searched for one. He's certainly there at the right time and might well have focused on the nutrition of the new breed, among his other duties. But since Mac and John almost never wrote, dad would not have not detailed knowledge of his work.
As a result of being developed specifically for smaller, urban households, the breed never had the size to satisfy the demands of restaurants. By the 1970s, it had nearly disappeared, and the Broad Breasted White had come into prominence. It is still extremely rare today, and is listed as Critical by the American Livestock Breeds Conservancy. It retains interest primarily among breed enthusiasts and those interested in a heritage turkey breed.