3rd vs 3th

I have seen this picture from 1940th. The most ineresting thing for me was the 3rd pig. Was it used to say 3th then?

I don´t know but doubt it. Proper use in current times is 1st, 2nd, 3rd, 4th, 5th … 10th, 11th, 12th, 13th … 20th, 21st, 22nd, 23rd, 24th, … 30th, 31st, 32nd, 33rd … etc.

I know, thank you. But I wanted to know if it is a typo or maybe an old rule.

Yeah, probably a typo.