depends on the area, if your state has larger deer (body wise not antler) then a 410 is pushing it.
My sister has a 410 she uses for hunting though (yet to shoot at a deer) butit shoots a nice pattern at 70 yards. If it was impossible to kill a deer with 410 then it would be banned in all states for deer.
I would suggest at least a 20 for deer though. Bigger slug, better chance of hitting a vital, and branches have less effect.