Hospital capacity is defined by several factors
- Lord skills
- Lord equipment
- Beast passive ability
- College research
- Lord rank (from elite war/adventure and some other end game events)
The gear I use will follow and the beast passive is just level 1. This equipment is easily obtained by anyone and the list is broken down in “what to forge”
The equipment shown here alongside beast passive level 1 and my research and lord rank provides a hospital capacity of 353590 as shown below.
this enables me to leave more troops home than the enemy can not kill me without at least 4 SOS although slaughter could be deemed a problem that’s very server dependant and definitely not encountered early in the game.
The hospital is very important and the troops within your castle when you are inactive should never exceed the hospital capacity. This includes returning gathering marches and means you can not lose army unless attacking. No defence should take loss apart from crown war where it can not be avoided.
you can see how to hide marches here