[LavoChain]

I personally don't use a set amount for all of the hamsters. I have some hamsters who will go two days and then empty their bowels, others need a more constant supply as they're greedy pigs! When a hamster arrives I always start by giving around 1 1/2 tbsp a day for Syrians and around 1-2 tsp a day to dwarfs dependant on breed and weight. It is soon easy to tell how much they actually need and I find that I avoid selective feeding most of the time by not over feeding them straight away.

I'd say the best way to tell if you are under or over feeding is to weigh the hamsters weekly to see if any significant weight fluctuations occur. Small gains or losses such as 3 grams or so is fine however if their weight is altering much more it could signify you're feeding too much or too little. It could also mean illness which is another great reason to weigh them. You can also keep an eye on their food stash to check that they're eating enough.