Fun fact: The ssh-agent equivalent for Windows that ships with PuTTY (pageant) has a limited amount of memory reserved to store the actual keys (8kb) which causes it to stop responding when more than 25 keys or so are used. Because they have no GitHub, no easy way to collaborate on the source, and the developers don't reply emails, this has gone unfixed for years, and even though PuTTY is open source and you can fix it yourself and use your build (which we did), the worst is that we quickly found out that almost every independent tool on Windows that relays on SSH copy pasted the source of PuTTY almost verbatim, since we found this bug in many places afterwards, including closed source applications.

Bottom line, set your workflow on Linux or at least bash for Windows if you manage or plan to manage many machines.