Poor girl

once again, the downside of breeding that people don't see until it is too late.
I really would go on that link - I know the lady who runs the group - they have done excellent work in finding foster mothers for pups - and personally, I really think your pups would benefit from it and give you some rest and peace of mind and the pups a much needed boost.
If they are quiet, unless there is something else going on, it does sound like they are not hungry. It's not unusual for the pups to suckle on each other either - usually the boys in the litter come off worst on that front
My last litter, there was only one boy - as you can imagine - he was the centre of attention
With regards to changing to goats milk at 2.5 weeks - I started weaning my last litter at 2 weeks because it was clear they were hungry - good job I did as mum stopped feeding completely at 4 weeks - she was dis-interested to start with - but fortunately, she did come around - she was an OK mum, - but she wouldn't clean bums
I suggest it because once they get onto food - you really will start to notice a difference in their growth rates.
You can get puppy porridge - but I use whatever food I am feeding mum and intend to feed the pups (last litter Pro-Plan) - pour boiling water over it and leave it to stand and then mush it - I also add some Lactol for the first couple of days (if you are using whelpi - then add this instead)
Initially I go in the whelping box with the pups and they suck it off my hands and fingers - great fun

- they soon get used to the idea - then I start feeding them out of bowls - I do a combination of individual and group feeding - these pups could benefit from feeding individually once you have them used to the idea of "proper food".
I also use rice pudding which they get when they go to bed - and as they develop and mum starts moving away - we start adding the foods that mum was eating such as chicken (shredded over the food initially), mince, oily fish - and rice pudding - they absolutely love the rice and it can be good for upset tums.
The other thing I use occasionally on top of goats milk is natural yogurt which is also good for their tums.
You might find an overhead heat-lamp more cost effective than putting the heating on - - they were about £15 when I bought mine, with replacement bulbs around £5 - I did buy some extra bulbs but didn't need them.
Heat lamps for poultry and other animals | Standard Heat Lamp with Energy Saving Switch | Buy 10 pay for 9 !
Some people are reluctant to use them as they can make the whelping box too hot for mum - obviously not a problem you are going to have.
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If you have a girl there who will go in and clean them - let her - if mum follows her - fabulous - just when they are doing this - don't take your eyes off them for a second - mothers can accidentally lay on, and crush pups when they are very young - but if they will help with stimulating for toileting etc - it takes a bit of the pressure of you.
ETA - I posted this before I saw kodakkukis post - thanks for clarifying