I received a new litter of kittens last night from a rescue. There are 6 kittens, 6 days old and a very young thin mom. The mom is very friendly, and very attentive to the babies. They are doing great. I am a little worried about her though. I set up food and litter for her. She has been eating like a horse, and needs the calories. She hasnt used the litter box yet, even though I have placed her in it 3-4 times in the past 24 hours. I dont see or smell anything. Could she be holding her bladder for this long? Thoughts?