The common term is multivitamins, usually it have high dose of vitamin B, C, etc. and it is water soluble. Fast growth is a combination of genetics, feeds, management. And this is the tricky portion, you need to have a balance of all of this.
Genetics is whether your chicks are from a company which have a good reputation in your area. A proven record.
Feeds= THere are now many companies that sells animal feeds, a good rule of thumb as a beginner is to buy the most popular or those within the top 3 feed company in your area. It means that they have a huge follower or satisfied customers.
Management= this is your part. Don't just go to the farm if you need to feed them or give them water. You need to monitor them every now and then. Stay with them, try to feel the place, the temperature, humidity, smell etc.