Sarah Josepha Hale, the author of Mary had a little Lamb is the one who had struggled for 20 years, over the period of 5 presidents to make Thanksgiving day a national holiday. Until then, only Independence Day and Washington Day were the national holidays in US. Lincoln was the one who made the Thanksgiving Day, the last Thursday of November, a national holiday. Roosevelt changed it to second Thursday in in 1940 to boost the economy of the nation. Hale also wrote that mashed and sweet potatoes, pumpkin pie, turkey and stuffing should be served on Thanksgiving Day. On the first Thanksgiving Day, different fowls, deer, flint corn and fishes were served. Till Thanksgiving Day, many a times thanks were offered to god for good crops, and supply ships.
This was the practice of Pilgrims who came in the Mayflower, and only 50% of them were Pilgrims. The turkeys are called turkeys because these guinea fowls were exported by the Turkey merchants. The Turkey shoot came up because of the tradition that turkeys were tied to the logs in the Thanksgiving Day mornings. Later people started gaming on shooting of the heads, the only visible parts of these birds. The information on first Thanksgiving Day is available from two passages of Edward Winslow and Plymouth Plantation of William Bradford, where the harvest festival is described.