how did the chicken cross the road ?

If it was a road safety sort of chicken, it would have used some sort of officially designated crossing such as perhaps a Belisha Beacon.

The first Belisha Beacon was erected in Wigan on the corner of Mesnes Street, and became operational on July 4, 1935.

In recent years the number of zebra crossings and Belisha beacons has fallen in the northern counties of England, being replaced by pelican crossings or puffin crossings, with pedestrian-controlled traffic signals.

Pelican crossing: n pedestrian crossing. An area of the road, marked with black and white stripes, where traffic lights stop cars so that pedestrians can cross. A contraction of “PEdestrian LIght CONtrolled crossing.” Yes, I know that would be “pelicon.” People were stupid back then.

The green man can be accompanied by a green bicycle to indicate that the crossing is designated for pedestrians and cyclists, continuing the bird-name theme, this type of crossing is called a Toucan crossing, as in, 'two can' cross. Another variation is the Pegasus crossing where the pedestrian is accompanied by a green horse to indicate that the crossing is designated for pedestrians and horses, for example, at Hyde Park Corner, London.

They seem to have run out of birds and are now using animal names like the zebra crossing. They were first used at 1000 sites in the UK in 1949 and are now in use all over the world