FIRST THE SAN DIEGO chicken exceeded its instructions and had to be legally restrained. Actually, it wasn't the chicken, which is a large, red foam-rubber suit. It was the man inside the chicken suit who got too popular and started making appearances that his employer, a radio station, had not approved. But then it wasn't really the man, Ted Giannoulas, who became a star; it was the man-cum-costume, the chicken, that made everybody laugh. And now that Mr. Giannoulas has been barred from wearing the suit, will he or the chicken ever be the same?

Such matters would not be worth clucking over if the Lone Ranger hadn't come along. But he has -- with an identity problem that means plenty to everyone involved. It seems that for 30 years the Lone Ranger has been Clayton Moore. More precisely, an actor named Clayton Moore has been portraying the masked man on television and in personal appearances -- and that has been his entire livelihood.

The trouble is that while the Lone Ranger is ageless, Mr. Moore is not. He is now 64, still trim, but not as firm-jawed as he was. And since the folks at Lone Ranger Television Inc. are bringing out a new Lone Ranger movie with a younger star, they want Mr. Moore to fade off into the sunset. He has refused to go. So the company went to court. Last week a Los Angeles judge agreed that the company owned the rights to the character and enjoined Mr. Moore from wearing the mask.

Mr. Moore, who wore his Lone Ranger outfit to court, promptly declared -- reportedly with tears in his eyes -- that he would keep fighting and "not let my public down." But it is not really his public; if he goes about in street clothes, Clayton Moore will be just another lone stranger. That's exactly what he fears. Yet after 30 years of hi-yoing, he should have learned that even those thrilling days of yesteryear do come to an end. No, he shouldn't trade his white hat for a chicken suit. Tonto would not approve. But Mr. Moore might well follow the lead of another retired champion of law and order, Sam Ervin. How about, "Hi-yo! I used to get along on silver bullets. But most people don't know me without my mask. That's why I always carry this credit card . . . "