Give her lots of water. What is the temperature. You may have to cool it down for her a little bit. 103 is not terrible, 104 would be too hot, and dangerous.
GSDs are not like small dogs that need very warm temperatures. They need plenty of water, and they need, it to be a little cooler. If she stops eating I would worry.
This first day the milk is just cholosterum, very important, but does not put much weight on the puppies. They generally lose weight the first day. After the first 24 hours, if they lose weight two days in a row, then supplementing is in order. Hard to say over the internet.
I have had 15 ounce puppies go down to 12/13 ounces on the first day, then they generally start climing. If they are suckling, they will be ok most likely.
How is the litter doing. Is it loud are they crying a lot -- that could be a problem. If they are sleeping and sucking that is probably just fine. If it is too warm, puppies will lay apart. If it is cooler puppy pile. Mom will stay with them if it is a little cooler and they will sleep right on and about her. If the puppies are piling and staying close to mom, and one is apart -- it could be in trouble.
I think you are probably ok, from what I am hearing. Only I am a little worried that she is too warm.
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