I estimate it taking at least 15k beetles to clean a well prepared deer skull within a few days. That can get expensive so most people will purchase 2500 or 5000 and give them a couple of months to grow their numbers. This will also give you time to "feel" them out and gain a better idea of how much they can consume and when they are ready to handle a deer sized skull.

Most taxidermists use large chest freezers because they seal well, are easily customized, hold large skulls/racks and are insulated. Some people use storage totes or aquariums. You can keep them in anything that your skulls will fit in as long as it will seal well enough to not let them out or let intruders in and is made of metal/plastic/glass so they can't chew through it. You will need to ventilate the enclosure by cutting at least one 3-4 inch hole and placing a screen over it. You can check out this video for more ideas on making your own enclosure https://youtu.be/64GiXYXwSis

I have never missed filling an order and you will not have to wait weeks for your order to ship. I ship every Monday and Tuesday. If you order anytime before Monday afternoon I will ship them the Monday IMMEDIATELY following the day you ordered them. If you purchase them between Mondays shipments and Tuesday at 2pm Mountain time I will ship them that Tuesday. I ship with heat packs depending on the season. Sometimes it can do more harm than good to send heat packs. They are very hardy bugs and ship very easily.

Start by skinning and removing as much of the flesh as you can without damaging the bone. Then remove the brain and eyes. If the skull is large enough to fit a spoon in the brain cavity that can make it easier. Use a piece of wire to break up the brain in smaller skulls. A garden hose with a spray nozzle may help to get it completely clean.  If you are not planning on keeping the lower jaw remove that also. Then dry the skull to the consistency of soft beef jerky before freezing it for atleast 3 days to kill off any hitchhiking insects that may contaminate your colony. Then add it directly to the enclosure, there is no need to thaw it first.

I recommend keeping them at around 80 degrees and at around 30% humidity. Do not worry about variations as long as they don't cook at over 100 degrees or freeze for an extended period of time they will be fine. Keep in mind that they are insects and have to survive wide temperature swings in nature to include overwintering.

I use a few inches of shredded paper but you can use different materials as a substrate. I have read that wood chips, cotton balls, shredded newspaper and paper litter will work as a substrate also as long as you don't use cedar. I recommend using Styrofoam as a pupating material but you can use corrugated cardboard or cotton balls also. They need somewhere to burrow into and hide while they change to an adult beetle or they may be cannibalized by the other larvae.