Are mealworms and seeds all you are offering the hedgehogs? If so, that is not sufficient nutrition for them. Mealworms, in particular, are not good for them. It would be best if you cut out the mealworms and seeds and offered them either hedgehog food or cat/dog food. It is especially important for them at this time of year, when they are preparing for hibernation to have really good nutritious food so that they can put on the right sort of condition to survive. Although, you may find that most of them have gone to hibernate already.