
Yes you can -I do it all the time with kittens as often when I have to handrear or top up there is also the risk of infection in the body. I also did it with my last litter of pups, the smallest pup was really poorly and not gaining weight. She's now 4 months old and fit as a fiddle. The tablets are really easy to crush. I think most vets would prescribe Synulox DROPS instead for such young animals, but I've yet to meet an animal that didn't hate the taste of the drops. If you crush the tablets in some milk they don't seem to taste it at all.
Edited to say I see you said DROPS -well you can try but like I said they hate the taste, maybe ask for tablets instead? I used just an eight of a tablet for my tiny toy pup.