Maybe there could be a feature where food in the food pen gets divided evenly? It's probably better if everyone only has 50 hunger than if a few creatu are full and everyone else is hungry. If the food can't be divided evenly, maybe hungrier creatu get the extra food? It kinda bugs me when I fill up the pen and a few creatu are full and everyone else is hungry.

In all honesty, I'm not sure if I fully understand what you're suggesting ;o; 

I think the food pen is a fair system, just in case you missed it I'm going to copy and paste how the food pen works below: 

How it works:
- Only feeds creatu located on your profile
- Will only feed creatu who have a hunger of less 70 out of 100 points.
- Automatically feeds each creatu a random item from food pen until that creatu had reached the required 70/100 hunger points, or you have ran out of food.

If you wanted all pets to be 100% full you can manually feed them, or maybe suggest that the "feed pets now" button in the food pen will fill up a pets hunger to 100%