I actually just had one of my cows still give 1493 food from milk and she's only got huge boobs and milk flow 2 with no other farm upgrades. All my other cows are reasonable numbers although none of them do have any milk flow modifiers.
Also looking at your code i saw this which doesn't seem to make sense.
var chefhelped = false
if chefmod > 0:
chefhelped = true
else:
chefhelped = true
At that point why bother with the if? Just set it to true