I'm trying to cause zombie pigmen to appear in larger groups of 10–20 at a time. I have the following rules:

potentialspawn.json

[{
    "remove": [ "minecraft:zombie_pigman" ]
}, {
    "biome": [ "Hell" ],
    "block": [
        "minecraft:netherrack",
        "minecraft:soul_sand",
        "minecraft:nether_brick",
        "minecraft:bedrock"
    ],
    "mobs": [{
        "mob": "minecraft:giant",
        "weight": 500
    }, {
        "mob": "minecraft:zombie_pigman",
        "groupcountmin": 10,
        "groupcountmax": 20,
        "weight": 500
    }]
}]

spawn.json

[{
    "spawner": true,
    "result": "default"
}, {
    "mob": "minecraft:giant",
    "result": "deny"
}, {
    "mob": "minecraft:zombie_pigman",
    "mincount": {
        "amount": 201,
        "perplayer": true,
        "mob": "minecraft:zombie_pigman"
    },
    "result": "deny"
}, {
    "biomes": [ "Hell" ],
    "mob": [ "minecraft:zombie_pigman" ],
    "mincount": {
        "amount": 101,
        "perplayer": true,
        "mob": [
            "minecraft:zombie_pigman"
        ]
    },
    "result": "deny"
}, {
    "mob": [ "minecraft:zombie_pigman" ],
    "isnotcolliding": true,
    "result": "allow"
}, {
    "result": "deny"
}]

However, I never see any groups spawn larger than 4–5 members.

Oh... and about the giants... I want to slow down the rate of spawning, but I still want to get the right size groups appearing. My theory is that if you give a heavy weight to some mob which then always gets denied, it will only pick the mob you really want to spawn part of the time, so the overall rate of mobs getting spawned is slower. I tried doing the same thing using the random rule, but then I only ever got individuals (i.e., no packs at all).

Here are the versions I'm using:

• Minecraft 1.12.2
• Forge 14.23.5.2847
• InControl 3.9.16

FWIW, I've also tried this in the overworld with cows. It produces the same result.

groupcountmin/max don't give guarantees. It just makes Minecraft attempt to spawn as many. There is nothing that can be done about that really

@McJty I ran into a similar issue, but yes I understand it's not In Control's fault, but the way that the vanilla spawner works.