My 23 months twins are aggressive,they hit each other’s, is that normal behaviour?

A. Of course it’s a normal behaviour there are two kids of the same age staying in the same house and the same would expect them to be because it’s common for kids to fight even if they would have been one year or two years apart they would have the same way hitting each other specially when it is boys or the gender of the kids are same it’s a very common thing to be seen