At the moment it is not possible to represent hail in the IFS because it would require a higher resolution than what is currently possible. The IFS does predict water vapour, cloud water, cloud ice, rain and snow. In addition, the parameter "Precipitation type" can indicate some other forms of precipitation, such as ice pellets, see:
https://apps.ecmwf.int/codes/grib/param-db/?id=260015
For more details on how precipitation is represented in the IFS, take a look at Chapters 6 and 7 in Part IV Physical processes of the ERA5 IFS (CY41R2) documentation:
