diff --git a/app/utils/data_access.py b/app/utils/data_access.py
index c4ffc3f4..4051284a 100644
--- a/app/utils/data_access.py
+++ b/app/utils/data_access.py
@@ -829,8 +829,12 @@ def add_herd(form, user_uuid):
     user = fetch_user_info(user_uuid)
     if user is None:
         return {"status": "error", "message": "Not logged in"}
-    if not (user.is_admin or (user.is_manager and form["genebank"] in user.is_manager)):
-        return {"status": "error", "message": "Forbidden"}
+    try:
+        genebank_id = int(form["genebank"])
+        if not (user.is_admin or (user.is_manager and genebank_id in user.is_manager)):
+            return {"status": "error", "message": "Forbidden"}
+    except (ValueError, KeyError):
+        return {"status": "error", "message": "Invalid genebank ID"}
 
     with DATABASE.atomic():
         try:
diff --git a/frontend/src/breeding_context.tsx b/frontend/src/breeding_context.tsx
index 5510cd6a..2081346b 100644
--- a/frontend/src/breeding_context.tsx
+++ b/frontend/src/breeding_context.tsx
@@ -244,7 +244,9 @@ export const WithBreedingContext = (props: { children: React.ReactNode }) => {
     if (!breeding.litter_size6w) {
       return Math.min(breedingUpdates.litter_size6w, 9);
     }
-    if (breeding.litter_size6w < breedingUpdates.litter_size6w) {
+    if (
+      Number(breeding.litter_size6w) < Number(breedingUpdates.litter_size6w)
+    ) {
       return (
         Math.min(breedingUpdates.litter_size6w, 9) -
         Math.min(breeding.litter_size6w, 9)
diff --git a/frontend/src/breeding_form.tsx b/frontend/src/breeding_form.tsx
index 5160cf00..9d3fb416 100644
--- a/frontend/src/breeding_form.tsx
+++ b/frontend/src/breeding_form.tsx
@@ -294,7 +294,7 @@ export function BreedingForm({
       return false;
     }
 
-    if (userInput?.litter_size6w > userInput?.litter_size) {
+    if (Number(userInput?.litter_size6w) > Number(userInput?.litter_size)) {
       userMessage(
         "Kullstorleken efter 6 veckor får inte vara större än kullstorleken vid födseln.",
         "warning"
diff --git a/frontend/src/individual_add.tsx b/frontend/src/individual_add.tsx
index 60707237..fb0f1ee7 100644
--- a/frontend/src/individual_add.tsx
+++ b/frontend/src/individual_add.tsx
@@ -416,7 +416,7 @@ export function IndividualAdd({
       );
       return false;
     }
-    if (individual.litter_size6w > individual.litter_size) {
+    if (Number(individual.litter_size6w) > Number(individual.litter_size)) {
       userMessage(
         "Kullstorleken efter 6 veckor får inte vara större än kullstorleken vid födseln.",
         "warning"
diff --git a/frontend/src/individual_breeding_form.tsx b/frontend/src/individual_breeding_form.tsx
index a4cf95fb..5f5f5dde 100644
--- a/frontend/src/individual_breeding_form.tsx
+++ b/frontend/src/individual_breeding_form.tsx
@@ -267,7 +267,7 @@ export function IndividualBreedingForm({
 
     if (
       (userInput.birth_date, userInput.litter_size) !== null &&
-      !(userInput.litter_size > 0)
+      !(Number(userInput.litter_size) > 0)
     ) {
       userMessage("Ange en kullstorlek större än 0", "warning");
       return false;
@@ -365,7 +365,7 @@ export function IndividualBreedingForm({
       const newBirthData: Birth = {
         date: breeding.birth_date,
         litter_size: breeding.litter_size,
-        litter_size6w: breeding.litter_size,
+        litter_size6w: breeding.litter_size6w,
         notes: breeding.birth_notes !== "" ? breeding.birth_notes : undefined,
         id: newBreeding.breeding_id,
       };