So were you previously getting more eggs and you have had a drop in production or is this the most eggs you have ever gotten?
You said you did a full coop clean, were there a lot of feathers in the bedding when you did this?
At 1.5 years these birds are probably just finishing up a molt and starting to come back into lay. The 9 month olds may or may not have ever started laying since they hit maturity at the same time of year that days started getting shorter.
How do their combs look in general? Big and bright red or smaller and pale?
You can check for mites in the evening (after dark in the coop, so after your light has been off for a bit) by taking a white sheet of paper and running it along the roost... if it's covered with red smears, you've still got a mite problem.
You said you did a full coop clean, were there a lot of feathers in the bedding when you did this?
At 1.5 years these birds are probably just finishing up a molt and starting to come back into lay. The 9 month olds may or may not have ever started laying since they hit maturity at the same time of year that days started getting shorter.
How do their combs look in general? Big and bright red or smaller and pale?
You can check for mites in the evening (after dark in the coop, so after your light has been off for a bit) by taking a white sheet of paper and running it along the roost... if it's covered with red smears, you've still got a mite problem.