Its not a great idea to run with multiple snapshots in a production setup as it slows things down. If you remove a snapshot in Hyper-V manager you might think that that's the job done.  Well it isn’t – all you have actually done is actioned the snapshot merge.  The actual merge can only happen when the VM is switched off and if its a large snapshot it can take several hours to complete and HyperV manager gives you either no information or at best just a line saying “merging ….” so you have no idea how far its progressed.

Using Powershell however you can run:

Get-WmiObject -Namespace "root\virtualization" -Query "select * from Msvm_ConcreteJob" | Where {$_.ElementName - eq 'Merge in Progress'}

Which will give you the output below including a percentage complete