Hi,
Good start with the birthing box, best put in a quiet warm place like next to a radiator, and with a cover inside especially how cold it is now. Kittens need to be kept warm. No need to worry about litter trays and weaning before kittens are 3 to 4 weeks old. But mum will need abit extra food now and after kittens are born.

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Amanjay Siamese & Animal Healer.