I have 2 mini lop female buns just over 1 year old. They’ve been out all last summer in their eglu but moved into house for the winter, so since about October have resided in a large indoor hutch in my kitchen. Over the past two weeks they have gone outside in the day for a few hours as the weather has slowly improved. Put them out today after breakfast in their indoor hutch which is very secure as is my garden, both rabbits very perky. They had usual pellets, Timothy hay and carrot & water. Nothing different. Got home at 3 and 1 has died and seems to have been dead a while. We are all so upset and don’t know what could have caused this. They are both strong bunchy buns. What would have caused her to die so suddenly like this ?