Do they serve kosher or vegan meals in prison? If so, do they consist of?
A very quick Westlaw search of the United States Code Annotated revealed a few pertinent case summaries. I haven’t read any of the actual cases, but the summaries are generally reliable:
Prison’s policy of supplying Orthodox Jewish prisoners with one frozen kosher dinner supplemented with nonkosher vegetarian or nonpork meals violated prisoner’s First Amendment free exercise rights, where reasonable alternatives existed, warden conceded that kosher meal could be supplemented with kosher foods at modest cost, and prison accommodated dietary requirements of other religious groups. Ashelman v. Wawrzaszek, C.A.9 (Ariz.) 1997, 111 F.3d 674, as amended.
Muslim prisoner’s right to practice his religion was not violated due to inclusion of pork in meals served during lockdown, since prison officials had no reason to know that prisoner was affiliated with the Muslim faith. Eason v. Thaler, C.A.5 (Tex.) 1996, 73 F.3d 1322.
Guarantees of the First Amendment are not limited to beliefs shared by all members of a religious sect, so that prisoner who claimed that his religious beliefs required a vegetarian diet was entitled to invoke First Amendment protections if his religious beliefs were sincerely held, even though not all members of his religious sect adhered to a vegetarian diet. LaFevers v. Saffle, C.A.10 (Okla.) 1991, 936 F.2d 1117.
Federal prison was required to provide Orthodox Jewish prisoner with diet sufficient to maintain prisoner in good health without violating Jewish dietary laws, but court would not mandate specific items of diet. Kahane v. Carlson, C.A.2 (N.Y.) 1975, 527 F.2d 492.
The main meals available are,
Kosher, Halal, Vegetarian, Vegan(this is mainly for Buddhists), Catholocism-strict.
Plus any as directed by medical practitioners.
Any prisoner requiring meals as part of a religious orthodoxy must also prove their involvement in that faith, and must attend all ceremonies and services demanded by it.