This particular book was part of "story time" that the teacher read to the class when I was in elementary school back in the 70s, so I'm a little fuzzy on the details. What I do remember is that some kids, and possibly a parent/guardian, travel to an alien planet. The aliens there have a problem: sulphur/sulfur is a vital nutrient to them, and their natural source has somehow run out.
I recall one of the kids - I think a little girl - solves their problem by giving the aliens her pet chicken. The yolk in the eggs she lays have enough sulphur to sustain them. I'm not sure if this was supposed to be a temporary fix until they found a more permanent source, of if they planned on breeding more chickens to make it a sustainable thing. The humans return to Earth at the end, I think.
The book would have come out no later than the mid-to-late 1970s. It was very "soft" sci-fi, written for a young audience. That's all I can remember.