Help with pop-door secure latching

I have a small fleet of "Mini-Hoops" that I use for my Muscovy to raise babies in. They have pop-doors so that the families can either go out into portable run material, or can actually free-range (age is generally the main factor).

These aren't the most secure shelters to begin with, however, most years it is flying predators that are a problem with babies, not ground predators like mink or coons. Thus, since I can easily have a line-up of moms wanting brooding space, I need to be able to move the shelters easily and operate them quickly.

The biggest issue is that I need some sort of a simple, but secure and quick to operate latch for the pop door:





It's hard to see in the first picture, but I've got two bits of swing chain, one on the door and one on the lower shelter pipe, and a breaching snap to clip them.

Here's a close-up of the snap:



Problems:
1. Getting the two bits of chain lined up so that the snap can go through is fiddly - particularly if I'm wearing gloves which I generally am.
2. One in the centre isn't as secure as something by the two edges, but two clips seriously makes the process more painful - we have 1 mini-hoop like that and I need better than that option.
3. I would *really* like the solution to be 4 to 6 inches up the door, so I'm not having to get my hands in the duck-shit multiple times per day!

Here's a picture from the inside:



I have considered ideas for the inside, but the mom's aren't keen on me "invading their baby safe zone", and there's an 18" high knee-wall at the hatch door I'd have to step over to fasten something on the inside. I'm willing to consider a brilliant option for this, but it sure would need to be easy to manufacture, install and operate, to convince me!

So my wonderful, experienced, brilliant permies - what ideas can you conjure up for me? I've been mulling this over for some time without any really great ideas, so I will admit I'm here to pick your collective brains. How does that Beatles song go, "Please, please, help me... help me?"

Have you considered making a "barn latch" rod and slot, either swiveling or sliding? It would be a one-handed operation with comfortable distance for your hand from the ground. But it might be prone to opening by animals, not being a hooked latch.
See these pictures; I assume yours would be oriented vertically to connect the bottom frame instead of side frame:
Sliding https://images.app.goo.gl/NMCnRtFhDpHr7wux5
Swiveling https://images.app.goo.gl/bJzYbpWzrrgF8bG69

Love that!  I found this:  https://www.reddit.com/r/redneckengineering/comments/g8lh1m/when_you_need_a_gate_latch_but_are_2_hours_away/

So, 1, to be secure, you need it to latch at the bottom really,  not midway up the door.  2, To keep your hands out of the poop, it needs to be operated from midway up the door or higher.
My vote would be a slide latch installed vertically. I would go for one on each side but you could do one in the middle. On the bottom, on the tractor frame you would put a piece of pvc pipe, an inch or 2, oriented vertically for the rod to slide into.  On the door i would use a wooden dowel aligned to go into that pipe installed with a couple of pieces of that same pipe, (like the picture in the earlier post of the gate slide),  only vertically instead of horizontally. You could use a smaller piece of pvc for the rod, or a metal pin bent at the top into an L for a handle, but It's easier to put a handle on a wooden dowel than a piece of pvc, which will break quickly, and harder to bend a metal rod, unless you have one lying around.

Could you run vertical pvc down the sides or even just the center to run a pin into the ground? Or re-fabricate the door so the pvc frame is on the outside and replace the corner 90's with t's to run the pins through? Might make the door more secure and the pins could be used to hold the door open too? A piece of rebar pin with a 90 degree handle at hinge point keeps duck poo off the hands.

I completely and totally adore the cheapest possible solution to every problem. We use a bit of the Toyota method and ask for answers to a problem five times and usually come up with a free answer. I have cobbled up so many door configurations (and spent a lot of time and money doing it) that I finally relented and bought Omlet doors. They're secure and automatic, powered by AA batteries. They fit my lifestyle well. Maybe this could be an option for you or somebody?

Had a similar problem years ago and installed slide latches, which a predator promptly fiddled open. Put a second slide latch on the other side of each door and had no more trouble with invaders.

Perhaps an S hook or carabiner could solve your attaching in the up position issue.  If you want to be able to do something with gloves on, it needs to be bigger and / or easier to handle.

Derek Thille wrote:Perhaps an S hook or carabiner could solve your attaching in the up position issue.  If you want to be able to do something with gloves on, it needs to be bigger and / or easier to handle.

Yes, I'm thinking about that too! There is already an S hook at the end of the chain used to hold the pop door in the up position.

I definitely don't want too many parts that ducks or geese will wander off with! These shelters also move 1 rectangle every day, so they need to stay light and with most bits hooked or tied on.

This is my current fix. It's a win in the "secure" department. It's a win in the "not right down in the dirt department. But it's a loose in the, "easy to operate with gloves on" department. Everything I needed was in our spare parts department, although the L  aluminium was new, as were the stainless bolts and the R-pin. I need 3 sets, and as of this afternoon, I have two sets installed! The third shelter got pressed into service before I had the time and good weather to install it, but it will happen in due time. BWD is happy with it as it is and her two foster goslings she hatched for me aren't old enough to be let out yet.



Here's a close up of the bracket and the R-clip. The white bar is a tube (upcycled from a friend's broken clothes drying rack) which is what makes sliding the R-pin in tricky. By fall, I will think of something I can fill the tube with at that end, to guide the R-pin, as I'm pretty sure that will make it easier to operate. I also increased the size of the hole the pipe is sliding through from the 1st installation to the second. I'm not sure I shouldn't go up one more size... wont' decide until I've tested # 2 installation.



Thanks to everyone for their input and ideas. I'm still open to more options and who knows what brilliant idea might come to us?