To be honest i have had these rats breeding for almost 2 years and have tried different things on how to feed them ! It does not matter how you feed them if your careful you will not need anything just put food in. There is no waste. There are a few that use feeder that can be made but what happens is the rats take the lab block out of the feeder anyway. So you can have a full feeder when you go to bed and get up in the morning and all the food is all over so i don't bother. I use the same amount of food in the tubs as i use in my breeder tubs ! There is very little waste either way.