ORIGINAL: Howler
I like to use duller broadheads to help the arrow stay in the bird.
Makes no sense! I want my blades to cut anything they touch and if they go all the way through, nothing worng with that. Buta head that is dull, isn't going to do the damage that a sharp one will!
I also have done like Roskoe does, I have slightly rounded the tip on my jackhammers, but keep the sharp blades!
It all has to do with KE and energy transfer from the broadhead to the birds body. Higher the energy transfer, the more likely you are to knock the bird over. Think of it like this, when you punch someone (which I have never done) do you do it with one finger or your whole fist. The whole fist, because it transfers the energy in a better way. Same thing applies to a broadhead. The arrow will still penetrate, but will stay in the bird, increasing the energy transfer, and also making it harder to lose the bird due to it flying off before dying.