> I do wonder at what point does McDonalds vertically integrate and process the beef themselves.

Never. McDonalds probably wants to avoid getting into a low profit margin, high liability business:

https://www.macrotrends.net/stocks/charts/TSN/tyson-foods/pr...

https://www.macrotrends.net/stocks/charts/MCD/mcdonalds/prof...

Look at the difference in trajectory and amount of profit margin and market cap (<5% and $20B versus 30%+ and $217B).

Tyson deals with the laborious and dirty work, as do McDonald’s franchisees. McDonald’s probably likes where it is, collecting royalties for “quality” control and real estate appreciation.