Foxes have 20 health

 "components": {
 "minecraft:type_family":
{ "family": [ "fox" ] }
,
 "minecraft:breathable":
{ "totalSupply": 15, "suffocateTime": 0 }
,
 "minecraft:navigation.walk":
{ "can_path_over_water": true, "avoid_water": true, "avoid_damage_blocks": true }
,
 "minecraft:movement.basic": {
 },
 "minecraft:jump.static": {
 },
 "minecraft:can_climb": {
 },
 "minecraft:collision_box":
{ "width": 0.6, "height": 0.7 }
,
 "minecraft:nameable": {
 },
 "minecraft:health":
{ "value": 20, "max": 20 }
,
 "minecraft:movement":
{ "value": 0.35 }