That really helps. I did check on them last night and this morning and there were still 16 running around. I will make sure that they have great access to water and feed.Congrats on the hatch! As far as numbers... much of what a hen can handle will depend on outside influences....
.... during warm weather they can handle more because the chicks will be able to tolerate not being totally covered after the first week or so. But if she can't cover them now you may need to intervene. Wait till late evening and go check on her (prefer with either a red light or very minimal lighting).... listen for a lot of cheeping and fussing. If you do hear a lot then watch to see if it appears that all the chicks can't be covered or are arguing. If that is the case you may need to provide an alternative heat source in the broody area or remove some to a brooder. A brinsea heat plate would work well, as would a 'lizard light' which is a ceramic heat bulb that would minimize disturbance but allow you to set up an auxiliary heat area or nest beside the broody for extra chicks to hang out or sleep.
.... make sure you are able to check on her multiple times a day while they are tiny if they are in an area with multiple levels (such as a coop run with a ramp to the coop). It may be hard for the mama hen to keep them all following her and you will probably need to help with transition from level to level. Setting up an alternative nesting area on the lower level will help the hen out, she can settle there during the day for breaks with the chicks.
..... food access must be easy and with enough space to allow them to all eat when mama shows them where it is.... same with water. So with that many chicks you may need to add an extra dispenser for both food and water.
... free ranging is a great way for mama to keep the little ones busy, but again, you may need to watch closely for the first few days she is out to help with stragglers. We always seem to have a 'wrong way Corrigan' in every clutch of chicks who is regularly getting lost or separated from the rest of the group. After a week or two the incidents reduce.
.... if your rooster is good with the chicks it makes it easier, I have 2 in particular that help with 'baby duties' and the chicks do respond well to them, same if you have another hen who the broody will tolerate.... but those assists are totally dependent on flock dynamics and personal attitudes. Flocks who are chick friendly are easier on a hen with a large clutch than flocks who are chick aggressive and the broody is constantly having to defend roaming chicks.
So my advice would be... let mama hen try to handle her little ones, but observe and be prepared to assist. I really feel that broody raised chicks just have an extra edge over their brooder counterparts when they are younger, so I do what I can to try to make it work out for them.