Examine bird off roost after dark, about the only way I ever do it.I'm not sure I want to do a butt check lol. Those are the only 2 pullets who dont let me hold them.
Wear a headlight or have someone hold a flashlight, keeping it dim until you have bird in hand.
Tho if both bird area close to laying, checking vent and pelvic bones might not tell the tale, you might have to catch them in the act to be sure.