Try advertising on Preloved too - there's lots of poultry on there. I agree you can't expect them all to go together. I've got 39 chickens, ducks and geese so more than the usual backyard keeper and couldn't even consider taking 45 in one hit. I'd have to have extra houses, runs etc. Nor would I take older birds - my oldest birds was a pair of two year old ducks, the rest have all been POL/hatching eggs. So the only people who could realistically take all yours in one go would be genuinely commercial, and they sound like they wouldn't be a good mix for a commercial breeder. Good luck - it'll be my problem in three years time!
H