Is there a way to switch all my bitcoin miners from one pool to another? Or am I stuck doing is one at a time?
Yes, you can select either many or all miners in the list and perform the Switch Pool operation on all selected.
There are multiple ways of selecting miners
1) Right click on a miner and click "Select all"
2) Select the first miner in list, hold down shift and click on the last miner in list.
3) Hold down control key while clicking on miners to select multiple
Another option is to select the group, and then you should be able to perform the operation on the entire group instead.