Why do you think Napoleon wanted to get rid of Snowball

Napoleon hired 9 dogs to chase snowball out of the farm and kill him ... Napoleon wanted to keep the animals busy so he gave them the responsibility of building a windmill.

The real reason that Snowball is expelled from the farm is that Napoleon regarded him (perhaps correctly) as a dangerous rival. Snowball is intelligent, a gifted leader, and very popular among the other animals ... With a public vote on the windmill looming, Napoleon uses his dogs to run Snowball from the farm.