Slough can refer to several things:
* A Slough is a type of wetland, similar to a swamp or marsh. There's no established collective noun for a group of wetlands. You might use descriptive terms like "a cluster of sloughs" or "a network of sloughs".
* To Slough can mean to shed skin, as snakes do. There's no established collective noun for a group of shedding animals. You might use terms like "a congregation of snakes shedding their skin" or "a group of animals sloughing off their outer layers."
If you're referring to a specific type of slough, it might be possible to find a more appropriate term. For example, if you're talking about a group of *sloughing snakes*, you could use the collective noun "nest" or "coil".
Let me know if you have more context, and I can help you find a more precise term!