Yes we had hot water bottles when we were kids. Was always told not to fill right to the brim. And then expell any air. Never had an accident. We also used heated bricks at the bottom of the bed.
Tony last year I tried to buy some sheep brains to try them out with butter and garlic sauce but I couldn’t find any anywhere. Now our cats and dogs probably eat better than a lot of people in third world countries, consuming the offal we don’t eat.