That's interesting because there's an Indian restaurant in our area run by Sikh's and they serve chicken and lamb in their restaurant.
http://www.sikhs.org/meat_au.htm
Throughout Sikh history, there have been movements or subsects of Sikhism which have espoused vegetarianism. I think there is no basis for such dogma or practice in Sikhism. Certainly Sikhs do not think that a vegetarian's achievements in spirituality are easier or higher. It is surprising to see that vegetarianism is such an important facet of Hindu practice in light of the fact that animal sacrifice was a significant and much valued Hindu Vedic ritual for ages. Guru Nanak in his writings clearly rejected both sides of the arguments - on the virtues of vegetarianism or meat eating - as banal and so much nonsense, nor did he accept the idea that a cow was somehow more sacred than a horse or a chicken. He also refused to be drawn into a contention on the differences between flesh and greens, for instance. History tells us that to impart this message, Nanak cooked meat at an important Hindu festival in Kurukshetra. Having cooked it he certainly did not waste it, but probably served it to his followers and ate himself. History is quite clear that Guru Hargobind and Guru Gobind Singh were accomplished and avid hunters. The game was cooked and put to good use, to throw it away would have been an awful waste.
The Gurus were loath to pronounce upon such matters as the eating of meat or ways of disposing of the dead because undue emphasis on them could detract from the main thrust of their message which had to do with spiritual liberation. However, Guru Nanak did reject by implication the practice of vegetarianism related to ideas of pollution when he said, 'All food is pure; for God has provided it for our sustenance' (AG 472). Many Sikhs are vegetarian and meat should never be served at langar. Those who do eat meat are unlikely to include beef in their diet, at least in India, because of their cultural proximity to Hindus.
In general Sikhism has adopted an ambivalent attitude towards meat eating as against vegetarianism. But if meat is to be taken at all, Guru Gobind Singh enjoined on the Khalsa Panth not to take kosher meat ie. Halal meat slaughtered and prepared for eating according to the Islamic practice. In fact it is one of the kurahits for every amritdhari Sikh. One who infringes it becomes patit (apostate).
There are no restrictions for the Sikhs regarding food, except that the Sikhs are forbidden to eat meat prepared as a ritual slaughter. The Sikhs are asked to abstain from intoxicants.
Some Indian food is very good. There is a lot of vegetarian-ism(?) among all the various religions, I think it's more of a tribal-regional preference than a religious one.
Goat, lamb, chicken, duck, goose and venison and dried fish are all commonly found in Indian dishes. They do eat a lot of veggies though, even if they are meat eaters, thats because veggies grow abundantly and in a huge varieties in much of India. The spices take some getting used to, so be careful.