The easiest way to use raw shrimp is to put some in a container of water and wait for them to decompose. Then use the water as the source of ammonia to add to the tank. It means you don't end up with bits of decomposing shrimp all over the tank, and the container can be cleaned up so much more easily. It would mean starting a second container before the first one had gone completely horrible so you'd have a continuous supply of ammonia water. Then a third, and so on till the cycle was finished.
The shrimp water could be allowed to get pretty high in ammonia as you'll dilute it a lot when it's added to the tank. You'd just need to test the tank after half an hour to see how near to 3 ppm, or later 1 ppm, you'd added, then add more if necessary.
If it was me though, I'd use a bottle of ammonia, it's so much easier. Provided you keep the top on when not dosing it and keep it away from any children, it is quite safe.