I've had multiple broody hens go up the ramp without all her chicks many times. It's a mess with lots of desperate chick siren alarm calls. The hens try their best to be sure.
The main thing is to get the chicks to walk their fluffy little selves up the ramp using their own 2 feet - it's a pain, especially when they decide to run all over the place, but they eventually do get it as long as they are made to go up the ramp.
For some reason they all make it OUT and down the ramp just fine but going back UP is a whole other thing.
Seems like by the 4th-5th night they figure it all out.
