When you say the chips burn up, do you mean they turn completely into ash, or do they become charred? Also, is the smoke white and heavy the entire time, or does it thin out after a few minutes?
The two main things that effect the rate at which smoke wood burns and produces smoke are the heat the wood is exposed to and the amount of air/oxygen present near the wood. The third factor that can effect burn rates is the size of the wood...larger pieces have less surface area, and will burn slower, so chunks will help to reduce burn rates. If it's burning up fast, there are a few tricks you can use to reduce burn rate, and they are to reduce the heat or proximity of the wood to the heat source (elevate smoke box/tray higher or reduce heat output) or reduce the air/oxygen getting to the wood...contain it in a foil pouch not in direct contact with the heat or flame, or in a burned-out/seasoned tin can with a loose fitting lid. If head clearance is an issue using a tin can, you can cut down the top of the can to make it shorter to fit between the water pan and smoke tray. If a smoke box is used instead of an open tray, fit the cover in the tightest position on the box and use foil or other metal to close the vents down more to restrict the air getting into the wood.
Fine tuning the smoke output may be challenging at first, so don't get discouraged...there's a learning curve for everyone when using a new smoker, and if you're new to smoking there will be lots of tricks you'll learn along the way...some work better for different smokers than others, but they're all worth finding and looking into and testing to find out what works well for you in different conditions and what doesn't. If you don't have access to chunks, start with reducing the air getting to the wood...that's the easiest to accomplish, and usually provides the most immediate and effective results. If this helps but doesn't quite get things where you want, reducing air to the wood would be my next choice, then raising the smoke tray an inch or two higher above the burner will add more reduction in smoke output due to less heat.
Chunks start slower, so a mix of chips and chunks is a good way to get the smoke going, as the chips will bring the smoke faster, while the chunks hold on for a longer duration. I use a mix quite frequently. With higher temp smokes and/or when dealing with windy/cold conditions, you will use more fuel to maintain chamber temps, and this is where you will notice that taking a few extra measures to control the smoke is the most beneficial.
Good luck with the yard bird smoke!
Eric
