Guinea pigs do not need handfed. Do not give them any formula or milk products!! They are born unable to digest lactose and they get very little milk from the sow. Guinea pig milk is very thin with little nutrition. The pups only need to drink once to get colostrum for immunity and after that they can survive on a diet of hay, pellets, and veggies. Even when a sow has a small litter the pups will be eating pellets by 3 days old. Guinea pigs only have 2 nipples because they do not need to nurse their young. If you want to encourage the pups to eat other foods offer pellets soaked in water, pedialyte, or fruit juice with no sugar added and fresh alfalfa hay with lots of leaves. Guinea pigs also benefit greatly from fresh vegetables, fruits, and safe forages like grass, clover, alfalfa, edible flowers, and nontoxic tree branches which have not been sprayed with chemicals or too close to traffic. I think our largest litter was 9 with one runt that didn't make it. The sow was so fat that when you set her on the linoleum floor she couldn't go anywhere no matter how fast her feet moved cause she couldn't get enough friction to push her belly along.
These are less than 24hours old and eating alfalfa and romaine lettuce with their mom and a younger sow that shared the same cage.
Awww, I want the little orange/brown(?) one. I used to breed them many years ago. That one reminds me of my dear sweet "Howie".
It's the one in the back in the pic at the top of this page.