You posted in the Tech to Tech where they mainly discuss HVAC and not hearth appliances, which a pellet stove is. Should have been posted in Fireplaces. I'll ask a Moderator to move it.
It would always help when asking questions about appliances to provide the make and model.
In general, pellets will feed by gravity unless they 'cross-bridge', which is when pellets that were made too long knit together like Pixi-sticks or like a beaver dam of logs. This usually happens in the auger channel and only with low grade pellets that do not meet the PFA requirements.
Sorry about that...I have a Quadra Fire Castile. I agree about the low grade pellets. I've tried a number of different types and have only found a couple of brands i like. The ones I like are no longer available in my area due to the time of year I'm told. The ones i am using right now are tiny in size which seem to make a lot of powder and is turning everything inside black. I find the bigger ones work better but still won't slide down into the auger. I have tried a few things but still no luck.
I have a Castile insert and used to work for Quad so I'm rather familiar with their hopper/ auger systems and I cannot recall a situation where the pellets failed to fall into the base of the auger screw except where physically blocked. Sure, some pellets will sit on the flat part of the hopper to the right as you face it but sooner or later they will fall down into the base of the hopper. Check your shutter adjustment that regulates how many pellets are exposed at one time to the base of the auger screw. If it is closed all the way, play with opening it in 1/4" increments as described in the owner's manual. This is something any homeowner can do and is expected to tinker with--adjustments based upon different fuels. If your auger fails to feed with a full hopper, look for obstructions or a problem with the vacuum hose and switch, which allow the auger to feed. If this only happens when the hopper level is low, you just need to periodically manually feed the rest of the pellets down so they form an air seal that allows the vacuum switch to close. The stove will shut down before you burn your last pellet as it requires a minimum level of pellets for this air seal.