diff --git a/beesdoo_base/models/partner.py b/beesdoo_base/models/partner.py
index 34a0e02..e96fbac 100644
--- a/beesdoo_base/models/partner.py
+++ b/beesdoo_base/models/partner.py
@@ -28,8 +28,13 @@ class Partner(models.Model):
 
     @api.multi
     def write(self, values):
-        if values.get('parent_eater_id') and self.parent_eater_id:
-            raise ValidationError(_('You try to assign a eater to a worker but this easer is alread assign to %s please remove it before') % self.parent_eater_id.name)
+        for rec in self:
+            if (
+                values.get('parent_eater_id')
+                and rec.parent_eater_id
+                and rec.parent_eater_id.id != values.get("parent_eater_id")
+            ):
+                raise ValidationError(_('You try to assign a eater to a worker but this eater is already assign to %s please remove it before') % rec.parent_eater_id.name)
         # replace many2many command when writing on child_eater_ids to just remove the link
         if 'child_eater_ids' in values:
             for command in values['child_eater_ids']:
diff --git a/beesdoo_easy_my_coop/models/res_partner.py b/beesdoo_easy_my_coop/models/res_partner.py
index d5a4145..d683df7 100644
--- a/beesdoo_easy_my_coop/models/res_partner.py
+++ b/beesdoo_easy_my_coop/models/res_partner.py
@@ -53,27 +53,31 @@ class Partner(models.Model):
         Check the maximum number of eaters that can be assigned to a
         share owner.
         """
-        self.ensure_one()
-        share_type = None
-        if self.cooperator_type:
-            share_type = (
-                self.env['product.template']
-                .search([('default_code', '=', self.cooperator_type)])
-            )[0]
-        # If the current partner owns no share, check his parent.
-        if not share_type:
-            share_type = (
-                self.env['product.template']
-                .search([
-                    ('default_code', '=', self.parent_eater_id.cooperator_type)
-                ])
-            )[0]
-        if (
-            share_type
-            and share_type.max_nb_eater_allowed >= 0
-            and len(self.child_eater_ids) > share_type.max_nb_eater_allowed
-        ):
-            raise ValidationError(
-                _('You can only set %d additional eaters per worker')
-                % share_type.max_nb_eater_allowed
-            )
+        for rec in self:
+            share_type = None
+            if rec.cooperator_type:
+                share_type = (
+                    self.env['product.template']
+                    .search([('default_code', '=', rec.cooperator_type)])
+                )[0]
+            # If the current partner owns no share, check his parent.
+            if not share_type:
+                share_type = (
+                    self.env['product.template']
+                    .search([
+                        (
+                            'default_code',
+                            '=',
+                            rec.parent_eater_id.cooperator_type
+                        )
+                    ])
+                )[0]
+            if (
+                share_type
+                and share_type.max_nb_eater_allowed >= 0
+                and len(rec.child_eater_ids) > share_type.max_nb_eater_allowed
+            ):
+                raise ValidationError(
+                    _('You can only set %d additional eaters per worker')
+                    % share_type.max_nb_eater_allowed
+                )
diff --git a/beesdoo_easy_my_coop/tests/test_res_partner.py b/beesdoo_easy_my_coop/tests/test_res_partner.py
index 28c750d..a65b110 100644
--- a/beesdoo_easy_my_coop/tests/test_res_partner.py
+++ b/beesdoo_easy_my_coop/tests/test_res_partner.py
@@ -77,6 +77,37 @@ class TestResPartner(TransactionCase):
             coop3.write({"child_eater_ids": [(4, self.eater3.id)]})
         self.assertIn("can only set", str(econtext.exception))
 
+    def test_multiple_eater_assignement_share_a(self):
+        """
+        Test adding multiple eater in one write.
+        """
+        coop1 = self.env.ref(
+            "beesdoo_base.res_partner_cooperator_1_demo"
+        )
+        coop1.write(
+            {
+                "child_eater_ids": [
+                    (4, self.eater1.id),
+                    (4, self.eater2.id),
+                    (4, self.eater3.id),
+                ]
+            }
+        )
+        self.assertEqual(len(coop1.child_eater_ids), 3)
+
+    def test_parent_assignement_to_eater(self):
+        """
+        Test adding a parent to multiple eater in one write from the eater.
+        """
+        coop1 = self.env.ref(
+            "beesdoo_base.res_partner_cooperator_1_demo"
+        )
+        eaters = self.eater1
+        eaters |= self.eater2
+        eaters |= self.eater3
+        eaters.write({"parent_eater_id": coop1.id})
+        self.assertEqual(len(coop1.child_eater_ids), 3)
+
     def test_is_worker_share_a(self):
         """
         Test that a cooperator is a worker based on his share type.