Share the unit file.

<?xml version="1.0" encoding="utf-8"?>
<unit dlc="Supplement2">
<model>
<unit mesh="Units/Tyranids/EliteWarrior"
material="Units/Tyranids/EliteWarrior"
idleAnimation="Units/Tyranids/TyranidPrimeIdle"
idleAnimationCount="3"
idleContinuously="1"
normalWeight="0.1"
scale="0.9 0.9 0.9"
bloodBone="Bone001"
walker="1"/>
</model>
<group size="3" rowSize="3" memberDeltaX="70" memberDeltaY="80"/>
<weapons>
<weapon name="Deathspitter">
<model>
<projectileWeapon mesh="Weapons/Tyranids/EliteWarriorGun"
material="Units/Tyranids/EliteWarrior"
fireInterval="0.533333333333"
bone="WeaponBone"
muzzleBone=".Muzzle"/>
</model>
</weapon>
<weapon name="Boneswords">
<model>
<weapon fireInterval="0.4"/>
</model>
</weapon>
<weapon name="FleshHooks" requiredUpgrade="Tyranids/FleshHooks">
<model>
<projectileWeapon muzzleBone="BloodBone" fireInterval="10.0"
effectFaceWeight="1.0"/>
</model>
</weapon>
</weapons>
<modifiers>
<modifier visible="0">
<effects>
<armor base="6"/> <!-- %armor base armor=4+ -->
<biomassUpkeep base="4.5"/> <!-- %biomassUpkeep base tier=7 factor=1 -->
<biomassCost base="90.0"/> <!-- %biomassCost base tier=7 factor=1 -->
<hitpointsMax base="12.0"/> <!-- %hitpointsMax base toughness=4 wounds=3 -->
<meleeAccuracy base="10"/> <!-- %meleeAccuracy base weaponSkill=5 -->
<meleeAttacks base="2"/>
<strengthDamage base="1.5"/> <!-- %strengthDamage base strength=4 -->
<moraleMax base="12"/> <!-- %moraleMax base leadership=9 -->
<movementMax base="3"/>
<productionCost base="42.0"/> <!-- %productionCost base tier=7 factor=1 -->
<rangedAccuracy base="6"/> <!-- %rangedAccuracy base ballisticSkill=3 -->
</effects>
</modifier>
</modifiers>
<strategyModifiers>
<modifier>
<effects>
<increaseInfantryScore base="1.0"/>
</effects>
</modifier>
</strategyModifiers>
<actions>
<attack>
<model>
<action animation="Units/Tyranids/TyranidPrimeAttack"
beginFire="0.733333333333"
endFire="2"
chargeAnimation="Units/Tyranids/TyranidPrimeCharge"
chargeBeginFire="0.3"
chargeEndFire="1.36666666667"
meleeAnimation="Units/Tyranids/TyranidPrimeMelee"
meleeBeginSwing="0.133333333333"
meleeEndSwing="0.666"/>
</model>
</attack>
<die>
<model>
<action animation="Units/Tyranids/TyranidPrimeDie"
sound="Units/MediumUnarmoredDie"
soundCount="4"
soundDelay="1.0"
voiceSound="Units/Tyranids/MediumDie"
voiceSoundCount="4"/>
</model>
</die>
<idle>
<model>
<action/>
</model>
</idle>
<move>
<model>
<action animation="Units/Tyranids/TyranidPrimeMove"
sound="Units/Tyranids/InfantryMove"
soundCount="4"/>
</model>
</move>
<genericUnitAbility name="Tyranids/SynapseCreature" passive="1">
<beginTargets>
<selfTarget>
<areas>
<area affects="Tile" radius="1">
<modifiers>
<modifier>
<effects>
<addTrait name="Tyranids/SynapseLink"/>
</effects>
</modifier>
</modifiers>
</area>
</areas>
</selfTarget>
</beginTargets>
</genericUnitAbility>
<genericUnitAbility name="Tyranids/ShadowInTheWarp" passive="1">
<beginTargets>
<selfTarget>
<areas>
<area affects="Tile" radius="1" excludeRadius="0">
<modifiers>
<modifier>
<effects>
<addTrait name="Tyranids/ShadowInTheWarp"/>
</effects>
</modifier>
</modifiers>
</area>
</areas>
</selfTarget>
</beginTargets>
</genericUnitAbility>
<subterraneanAssault name="Tyranids/SubterraneanAssault"/>
</actions>
<traits>
<trait name="ExtraInfantryArmour" requiredUpgrade="Tyranids/ExtraInfantryArmour"/>
<trait name="Fleet" requiredUpgrade="Tyranids/AdrenalGlands"/>
<trait name="FuriousCharge" requiredUpgrade="Tyranids/AdrenalGlands"/>
<trait name="Tyranids/InfantryUpkeep" requiredUpgrade="Tyranids/InfantryUpkeep"/>
<trait name="Tyranids/ToxinSacs" requiredUpgrade="Tyranids/ToxinSacs"/>
</traits>
</unit>

So, if I'm correct, you created a squad of Tyranid Prime, right?
However you used the Tyranid Warrior file as a basis for the model.

You should use bloodBone="BloodBone", just like in the Prime file.

Also please, if you need to copy paste code in the future use the 'code' tag so it keeps the space and is more easily readable.
You can also use pastebin, I think it keeps the formatting :)

Deep thanks for your help, and sorry for the copy paste that wasmy very first subject on steam ^^
I gotta test out this modification!