I played the game a few months ago and loved it.  I'll be running an island at some point in the future, and I'm not sure how many defensive dice to give to minions who gang up.

When minions gang up to attack, they can still be attacked individually.  Can those minions still use their ability and name dice defensively?  It doesn't seem right to let them defend with the same ability dice that went into the shared attack, but I could see giving them the name die.  It would be as though they allocated their name dice to defense but put all their ability dice into the shared attack, which earned the group an extra name die.

For example, the Clay Pigeons of Antioch have d4 battle ability and their master's name is d10.  They attack with d8+1 (bow) by dropping sharp rocks from high above the ruined amphitheatre. Six of them gang up to attack at +7 with 1d10 1d8 and 6d4, and they defend with nothing, unless they can take the name dice on both defense and offense.

With Minions, you allocate dice just the same as you do with named character. But then on attacks, you apply the group bonus.

For example, lets say you have those Clay Pigeons of Antioch. They have the stats you describe: Battle d4, Masters Name d10, and d8+1 bow.
The GM allocates dice: he puts the Battle and Bow dice on Attack, because he has to, giving d4+d8+1.
He can use the name on either attack or defence, IIRC (if a player using a bow can put his name dice on defence, so can the minion). Assume he does, for a d10.

Then the minion group attacks, with 6d4 +d8 +7.
Whenever anyone attacks it defends with the Name die of d10.

Next turn, the birds use the Name Die for attack, so the group (assuming they haven't been split up at this point) now roll 6d4 + d8 +d10 +7 for their attacks.
If they get attacked, they roll nothing for the defence - exactly the same situation as for a bow-using hero who allocates his Name Die on attack.

If the minions have been split up into two groups of three, both groups get the Name Die, and can separately allocate it to attack or defence. If they put it on defence, they don't get to use it for the attack roll.

If they get hacked up and seperated so that there are now three remaining minions, each of which is a different 'group' - each 'group' still gets the Name Die and can each allocate it to attack or defence separately.

There's nothing special about the way minions get their basic dice, and they allocate them to attack and defence as the GM desires.
But then, at the moment a minion group attacks, the GM works out their bonus for numbers and adds this to the attack.

Yep. As usual, Darren is 100% right.

Thanks, Darren.  That makes perfect sense.