Yuan-Ti are not given the ability to hibernate...
Within 5e lore, Yuan-Ti are never expressly given the ability to hibernate. They appear in the Monster Manual and their lore is further fleshed out in Volo's Guide to Monsters, and no mention of hibernation is made in either of those two books. (I am unfamiliar with the lore of older editions, but I am not aware of any past Yuan-Ti lore that mentioned hibernation either).
... so do as you see fit.
The DM is empowered to add on to, modify, or remove elements of the world as befits the game they want to run and the story they wish to tell. If you think that giving Yuan-Ti the ability or requirement to hibernate would be interesting, then by all means, go ahead and do so! This is ultimately your (and your players') game, not WOTC's, and creativity and expansion is very much encouraged.