Hi wondered if anyone can help

My bitch has become a foster mum for a litter of 2 week old pups due to the mum becoming very poorly. She will feed them but wont sleep with them etc. They are in a seperate box to mine.

I only have one heat mat as I never expect to have two litters at any one time. I have put a puppy pen round the box with blankets pegged to it to keep the draught out. The temp in there box is 20 0c is this warm enough or should i put a warm hot water bottle in?

Many thanks

Its the fluctuation of temperature that could be the problem for pups with no constantly maintained heat source...like their mother for example.

Keeping a source of heat they can get to will help in this weather, cool at night and warming up considerably by day. So a microwavable slow heat release pad would help.
Cant you borrow another heat pad from a friend?