Gregory is a farmer and every morning he makes sure to harvest the eggs of his chickens. He has 72 chickens and 12 chickens in each cage, so a total of 6 cages. Each of his chickens lays only one egg per day.

One morning, Gregory suddenly found out that in cage 1, the 4th and 7th chicken did not lay any egg for the day. He then thought that maybe the chickens are stressed. Then the next day, the same happened to 2 chickens in cage 2. The 9th and 12th chickens had no eggs. The next day, only the 6th chicken in cage 3 and the next day the 2nd and 8th chickens in cage 4.

He then saw a pattern that every day a new cage was having a problem. So, he planned to guard cage 5 the whole night. While guarding that night, he heard movement and rushed to the cage and saw a shadow. He quietly watched the person and saw that they were stealing his eggs. The thief ran away after stealing an egg. Gregory checked and found out that the lost egg was from the 5th chicken.

Gregory had enough and planned to set a trap. Can you help Gregory capture the thief? If you will help Gregory, on which chicken(s) will you put the trap?


Gregory has a brother named Christian


Cage 5 was ransacked on a Friday night



Born in 16th century, Gregory is very superstitious


After investigating, Gregory found out that the thief was Jason from the other town

  • 3
    $\begingroup$ I suspect they were Easter eggs... $\endgroup$ Aug 28, 2015 at 9:20
  • $\begingroup$ haha but I thought it should be held on a Sunday? $\endgroup$
    – Mekalikot
    Aug 28, 2015 at 9:25
  • $\begingroup$ Is it relevant how the numbers are distributed in each cage? As in: is it relevant if they are 4x3, 3x4, 2x6, 6x2, .. and in what order they are numbered? (I was thinking Braille, but that's 6 dots per character) $\endgroup$ Aug 28, 2015 at 9:37
  • 2
    $\begingroup$ Does Gregory like to leap around a lot? $\endgroup$ Aug 28, 2015 at 11:11
  • 1
    $\begingroup$ That's an egg-cellent puzzle ! $\endgroup$ Aug 28, 2015 at 11:31

1 Answer 1


Short answer

It's about

days of the week on different months of the year.

The answer is

the 1st and 10th chickens will be targeted in the 6th cage.

Fuller explanation

There are 12 chickens in each cage, corresponding to the 12 months of the year. "Gregory" is a hint to use the Gregorian calendar; "Jason" is a hint to the months (JFMAMJJASOND); and "Friday night" is a hint to the days of the week.

  • On the first day, the 4th and 7th chickens' eggs are stolen; in 2013 (say), April and July began on Mondays.
  • On the second day, the 9th and 12th chickens' eggs are stolen; in 2014 (the next year), September and December began on Mondays.
  • On the third day, the 6th chicken's egg is stolen; in 2015, June began on a Monday.
  • On the fourth day, the 2nd and 8th chickens' eggs are stolen; in 2016, February and August will begin on Mondays.
  • On the fifth day, the 5th chicken's egg is stolen; in 2017, May will begin on a Monday.
  • Finally, January and October are the only months in 2018 which will begin on a Monday, so it's the 1st and 10th chickens the thief will target in cage 6.

Thanks to f'' and others for help with the solution. And nice puzzle :-)

OP's intended explanation

It's all about Friday the 13th. Cages 1-6 represent the years 2001-2006 while the 12 chickens represent the months. There were Friday the 13ths in April and July 2001, September and December 2002, June 2003, February and August 2004 (leap year, like 2016), May 2005, and January and October 2006.

  • 1
    $\begingroup$ April and July in 2014 began on Tuesdays! $\endgroup$
    – Christoph
    Aug 28, 2015 at 10:52
  • $\begingroup$ I think you're very close to the answer but indeed Monday doesn't work and also thursday and friday not $\endgroup$
    – Ivo
    Aug 28, 2015 at 10:58
  • 1
    $\begingroup$ @Christoph In any leap year, Jan, Apr, and Jul will start on the same day. In any non-leap year, Feb and Aug won't start on the same day. I think the OP may have slipped up... $\endgroup$ Aug 28, 2015 at 11:11
  • 1
    $\begingroup$ My guess is you should take the year 1582 :) that's in the 16th century and is the year the Gregorian Calendar was introduced. You'll see then that indeed Sunday is skipped. I think everything fits. The answer will then be that on the 6th day chicken 1 and 10 will be stolen $\endgroup$
    – Ivo
    Aug 28, 2015 at 11:12
  • 2
    $\begingroup$ To add the explanation to the answer: it's all about friday the 13th. Cages 1-6 are years 2001-2006. 12 chickens are months. Jason is also the Jason character is friday the 13th. Great job guys, it's my first original puzzle lol $\endgroup$
    – Mekalikot
    Aug 28, 2015 at 15:07

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