You'll be delighted to hear that there are vegetarian, kosher, halal & carnivorous versions of rat packs however, there is absolutely no guarantee that you can realistically expect to be fed on exclusive dietry needs or expectations.
If you look at the amount of Calories a RM recruit burns on Recruit Training, you are going to be extremely hard pushed to maintain the balance on a vegan diet - something's got to give.
There are ethical considerations that you will have to confront- How do you feel as a vegan killing bunny floppits, gutting & cutting them up for example?
Nah mate it would'nt be pratical. Even if there was Vegan compo the QM would never get it out to you, You would get a big fat f off. You can't be fussy in the Corps mate and the majority of your diet throughout will be pretty poor believe me.
Bunnies are tasty even if you don't need to survive.
Royal Bunny Stew
1) Take one LIVE, cute looking bunny
2) Ask Royal to break its neck
3) Skin and gut it
4) Place in large pot with red wine and freshly chopped wild leeks
5) Place over hot fire
7) When you open the pot a charred rabbit will be stuck to the bottom of the pan with charred leeks. Eat.
Carbonised rabbit is no different from carbonised leeks. So you can eat it without a guilty conscience!