I would say druids are like any other person. Some are vegan and others aren't. It is more of a personal choice than a druid sect code. Also don't confuse Druids with Paladin orders or clerical orders. Druids do have some codes and rites they follow, but for the most part they are pretty relaxed about most things. The only thing I remember about druids, and I'm not sure if this is still expected in 5E, but they couldn't wear metal armor and had specific weapons they could only wield. Scimitar, maces, clubs, quarterstaff, sling, daggers, and bows I think were allowed? I rarely played druids so my memory is foggy on what they were allowed to wield. As far as eating animals never said one way or the other about that. That was usually just a PC choice for their character to be vegan or not.