This is a story I read at least 20 years back. I can remember a number of scenes, but frustratingly few key words that I've been able to make a meaningful search on.
Probably childrens or possibly young adult. It's longer than a short story - probably novella length.
Protagonists are boy and girl (I think siblings) attending a school on another planet. It's been settled a while, but within relatively recent memory. During the initial exploration, some eggs were found but no adult forms; two eggs were sent back to Earth for study, and a scientist on the planet experimented with the remaining two and created a race of beings that were sentient but of limited intelligence, who became servants to the humans. There was a line (paraphrased) 'Wasn't she pleased at creating [the servants]? No, she was furious - she thought she should have seen what hatched naturally!'
The servants have some form of rebellion brewing, and they use metallic (?silver) nail varnish to communicate using a code by telegraphing the sun. It's dismissed as a fashion fad by the humans.
There is a scene where the protagonists servant has used a cloth to clean something up they shouldn't have been using, and the thought process is described 'He could wash the cloth - but that would waste the [...]. He could throw the cloth away - but that would waste the cloth. So in the end he dug a hole and buried it.'
The protagonists are planning some sort of flight display during a festival, using a kind of jet-assisted take off booster. They discover the rebellion, and use the flight to thwart it somehow - I think mirrors were involved somehow, subverting the servants use of heliography.
The servants may have been called 'Gullivers', but that might be my memory inventing a name...
I don't believe it was particularly famous, and was probably read at the time I was picking up anything labelled science fiction in the library.