Enough air during shipping?

I am about to ship a snake out tomorrow. I am getting the heatpacks today and have the insulated box all ready.
Now, how about air during shipping? I have gotten 3 snakes shipped to me and they were packed the same; in a styro box, etc. So please re-assure me that the snake will have enough air in there! I put some small holes in the ziplock container that the snake is going into. But in that styro box, will he have enough air?

Honestly snakes have very minimal oxygen requirements over a 24 hour period. I have shipped over 100 snakes and received about 25. All were in sealed boxes, none had a problem. I do always try to feed about a week before I ship though this makes them empty during transport and usually quick to eat for the new owner too.

Out of all the shipments I have received, some shippers just ship in a completely sealed box, some poke just a hole in each side, and I have actually received a box with a rather large hole cut out of the cardboard and the styrofoam, then sealed with a screen. I personally don't poke any holes or cut anything out, and haven't had any problems... At this time of year I would want it to stay warm in the box and not have cool air seeping in, but that's just me.