I set my broody hens and get 2-4 clutches a year. I have orpington/australorp type mixes, so large fluffy girls. I have no idea why but was ALWAYS told/taught by my grandmother to 1. never set a hen with an even number of eggs and 2. never set a hen when it's supposed to thunderstorm in the first week. So I tend to set 11, or 13. I have on occasion incubated eggs and given them to a hen to raise. I think the most chicks I gave was around the 30 mark BUT it was mid summer and the weather stayed warm at night. The group had a nice sheltered house and brood pen (8x8 enclosed yard). It was ok that they all didn't fit under her as they rotated sleeping positions from under to on-top etc. She taught them to eat and be chickens and I didn't need a heat source - win-win-win. Some suggestions though: A hen will not just accept anything you poke at her. You need to fool her into thinking these are hers and she hatched them. So set her with eggs and set the incubator at the same time. As they hatch from incubator and her 'own' eggs are hatching just poke them under her to finish drying etc. She can't count at this point. If you wait till she comes off the nest and starts feeding etc - She can count and will reject and even kill the 'foreign' chicks. Sometimes you can get lucky if you introduce them at night etc. but I've not had much luck this way. You can do the fooling thing and combine clutches, I've done this several times. Say you set two hens at the same time, one hatches 90% but the other only hatches 10%. Poke the 10% under the 90% or if the 90% is a bad mother give them all to the 10%. Then break or reset the other hen if you feel like it. Hens set for 21 days but they don't count so well nor can they tell the age of a chick very well. So say you have a hen with 10 babies and she gets killed. Another hen sets but the eggs are bad, or you haven't given her 'good' eggs yet. Sometimes you can fool her into taking the orphans but this depends on how good a mother she is. Some are really picky about being moved/disturbed etc. and others could care less. Hope this gives you some ideas.