all day / all the year round

Question

1. In Sugarcandy Mountain it was Sunday seven days a week, clover was in season all the year round, and lump sugar and linseed cake grew on the hedges.

2. Even the ducks and hens toiled to and fro all day in the sun, carrying tiny wisps of hay in their beaks.

These was quoted from Animal Farm. I googled the difference between all + day/month/year and all + the + day/month/year, and found that the expression with the is quite old-fashioned expression. That makes sense because Orwell lived in the old time. However in the #2 sentence, the expression without the is used.

1. What's the difference in nuance between these two sentences? (all the year round / all day)

2. Are they exchangeable? (e.g. all year round / all the day)

3. What's the point in keeping this inconsistency in the same book?

Answer 1

This might just be natural variation of expression. Good writers (and there are none better than Orwell) will vary their language to keep things from becoming flat.

However in this case I note that the first extract is actually a character speaking. It is the raven, Moses, a pet raven kept by Jones. The use of "the" might be to indicate how Moses speaks - slightly old fashioned, slightly elevated, slightly fancy... it is quite subtle.

In the second extract the narrator is speaking in simple plain terms. Also "All the day" is not a common expression, even in fancy speech.

However, this has strayed into literary criticism. There is very little difference in meaning, but the plain form doesn't require "the". "All year round" is common and very acceptable. "All the day" is rare, but "All the day long" is possible.