Dog food is not a good idea. Dog food is offten very high in protine which can cause he to be constipated. It also mat hav vits that a beardie should not eat.
If you want to give a little more variety and keep your food cost down, do try the BB foods. Buy the smallest jar and only feed it like 2x in one week and only do this 2x per month. As mentioned to offten can lead to not only runny poos but they get spoiled by being hand fed. It is a good thing to have around if your beardie ever gets stoped up as well. You can use BB squash, peas, green beans, carrots & Sweet potato. Try to avoid fruit bb foods other than one dose per month as treat because they have alot of sugar. You can also do a veggie mixed with chicken but be carefull they dont have cereal (Brown rice is ok) nothing else in it.
Get a bb med syring and feed 1cc at a time. Im not sure how old your dragon is but at 6 month my guy could eat up to 3 cc at a time. Dont feed more than that though. To feed just dap a little on his nose and he will lap it off. he may want to grab the syring and shake it, in which you can squirt a very small amount into his mouth. try to aim it to the side of the mouth so it doesnt aperate him. he will let go when he has enough.