Leopard Frogs can go dormant if they feel there is a scarce amount of food and the humidity is low. They can go dormant on land actually and in the wild have been found hibernating on land in articles I've read. These frogs are more involved on land then you would assume. You can dig them up just to make sure they are dormant or if they are dead. You can increase humidity and maybe feed them more and that should help them with keeping active. They love to bask so in the winter if you have a UVB light they may benefit from it. You can buy a UVB light at a pet store if you don't have one. A 13watt works fine. They sell humidity gages too. Hope you find them!
Sent from my BLN-L24 using Tapatalk